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     avrdude - driver program for ‘‘simple’’ Atmel AVR MCU programmer


     avrdude -p partno [-b baudrate] [-B bitclock] [-c programmer-id]
             [-C config-file] [-D] [-e] [-E exitspec[,exitspec]] [-F]
             [-i delay] [-n] [-O] [-P port] [-q] [-s] [-t] [-u]
             [-U memtype:op:filename:filefmt] [-v] [-x extended_param] [-V]
             [-y] [-Y]


     Avrdude is a program for downloading code and data to Atmel AVR
     microcontrollers.  Avrdude supports Atmel’s STK500 programmer, Atmel’s
     AVRISP and AVRISP mkII devices, Atmel’s STK600, Atmel’s JTAG ICE (both
     mkI and mkII, the latter also in ISP mode), programmers complying to
     AppNote AVR910 and AVR109 (including the Butterfly), as well as a simple
     hard-wired programmer connected directly to a ppi(4) or parport(4)
     parallel port, or to a standard serial port.  In the simplest case, the
     hardware consists just of a cable connecting the respective AVR signal
     lines to the parallel port.

     The MCU is programmed in serial programming mode, so, for the ppi(4)
     based programmer, the MCU signals ‘/RESET’, ‘SCK’, ‘MISO’ and ‘MOSI’ need
     to be connected to the parallel port.  Optionally, some otherwise unused
     output pins of the parallel port can be used to supply power for the MCU
     part, so it is also possible to construct a passive stand-alone
     programming device.  Some status LEDs indicating the current operating
     state of the programmer can be connected, and a signal is available to
     control a buffer/driver IC 74LS367 (or 74HCT367).  The latter can be
     useful to decouple the parallel port from the MCU when in-system
     programming is used.

     A number of equally simple bit-bang programming adapters that connect to
     a serial port are supported as well, among them the popular Ponyprog
     serial adapter, and the DASA and DASA3 adapters that used to be supported
     by uisp(1).  Note that these adapters are meant to be attached to a
     physical serial port.  Connecting to a serial port emulated on top of USB
     is likely to not work at all, or to work abysmally slow.

     Atmel’s STK500 programmer is also supported and connects to a serial
     port.  Both, firmware versions 1.x and 2.x can be handled, but require a
     different programmer type specification (by now).  Using firmware version
     2, high-voltage programming is also supported, both parallel and serial
     (programmer types stk500pp and stk500hvsp).

     The Arduino (which is very similar to the STK500 1.x) is supported via
     its own programmer type specification ‘‘arduino’’.

     The BusPirate is a versatile tool that can also be used as an AVR
     programmer.  A single BusPirate can be connected to up to 3 independent
     AVRs. See the section on extended parameters below for details.

     Atmel’s STK600 programmer is supported in ISP and high-voltage
     programming modes, and connects through the USB.  For ATxmega devices,
     the STK600 is supported in PDI mode.  For ATtiny4/5/9/10 devices, the
     STK600 and AVRISP mkII are supported in TPI mode.

     The simple serial programmer described in Atmel’s application note
     AVR910, and the bootloader described in Atmel’s application note AVR109
     (which is also used by the AVR Butterfly evaluation board), are supported
     on a serial port.

     Atmel’s JTAG ICE (both mkI and mkII) is supported as well to up- or
     download memory areas from/to an AVR target (no support for on-chip
     debugging).  For the JTAG ICE mkII, JTAG, debugWire and ISP mode are
     supported, provided it has a firmware revision of at least 4.14
     (decimal).  See below for the limitations of debugWire.  For ATxmega
     devices, the JTAG ICE mkII is supported in PDI mode, provided it has a
     revision 1 hardware and firmware version of at least 5.37 (decimal).

     The AVR Dragon is supported in all modes (ISP, JTAG, HVSP, PP,
     debugWire).  When used in JTAG and debugWire mode, the AVR Dragon behaves
     similar to a JTAG ICE mkII, so all device-specific comments for that
     device will apply as well.  When used in ISP mode, the AVR Dragon behaves
     similar to an AVRISP mkII (or JTAG ICE mkII in ISP mode), so all device-
     specific comments will apply there.  In particular, the Dragon starts out
     with a rather fast ISP clock frequency, so the -B bitclock option might
     be required to achieve a stable ISP communication.  For ATxmega devices,
     the AVR Dragon is supported in PDI mode, provided it has a firmware
     version of at least 6.11 (decimal).

     The USBasp ISP and USBtinyISP adapters are also supported, provided
     avrdude has been compiled with libusb support.  They both feature simple
     firmware-only USB implementations, running on an ATmega8 (or ATmega88),
     or ATtiny2313, respectively.

     Input files can be provided, and output files can be written in different
     file formats, such as raw binary files containing the data to download to
     the chip, Intel hex format, or Motorola S-record format.  There are a
     number of tools available to produce those files, like asl(1) as a
     standalone assembler, or avr-objcopy(1) for the final stage of the GNU
     toolchain for the AVR microcontroller.

     Avrdude can program the EEPROM and flash ROM memory cells of supported
     AVR parts.  Where supported by the serial instruction set, fuse bits and
     lock bits can be programmed as well.  These are implemented within
     avrdude as separate memory types and can be programmed using data from a
     file (see the -m option) or from terminal mode (see the dump and write
     commands).  It is also possible to read the chip (provided it has not
     been code-protected previously, of course) and store the data in a file.
     Finally, a ‘‘terminal’’ mode is available that allows one to
     interactively communicate with the MCU, and to display or program
     individual memory cells.  On the STK500 and STK600 programmer, several
     operational parameters (target supply voltage, target Aref voltage,
     master clock) can be examined and changed from within terminal mode as

     In order to control all the different operation modi, a number of options
     need to be specified to avrdude.

           -p partno
                   This is the only option that is mandatory for every
                   invocation of avrdude.  It specifies the type of the MCU
                   connected to the programmer.  These are read from the
                   config file.  If avrdude does not know about a part that
                   you have, simply add it to the config file (be sure and
                   submit a patch back to the author so that it can be
                   incorporated for the next version).  See the sample config
                   file for the format.  Currently, the following MCU types
                   are understood:

                   Option tag   Official part name
                   1200         AT90S1200
                   2313         AT90S2313
                   2333         AT90S2333
                   2343         AT90S2343 (*)
                   4414         AT90S4414
                   4433         AT90S4433

                   4434         AT90S4434
                   8515         AT90S8515
                   8535         AT90S8535
                   c128         AT90CAN128
                   c32          AT90CAN32
                   c64          AT90CAN64
                   m103         ATmega103
                   m128         ATmega128
                   m1280        ATmega1280
                   m1281        ATmega1281
                   m1284p       ATmega1284P
                   m128rfa1     ATmega128RFA1
                   m16          ATmega16
                   m161         ATmega161
                   m162         ATmega162
                   m163         ATmega163
                   m164         ATmega164
                   m164p        ATmega164P
                   m168         ATmega168
                   m169         ATmega169
                   m2560        ATmega2560 (**)
                   m2561        ATmega2561 (**)
                   m32          ATmega32
                   m324p        ATmega324P
                   m325         ATmega325
                   m3250        ATmega3250
                   m328p        ATmega328P
                   m329         ATmega329
                   m3290        ATmega3290
                   m329p        ATmega329P
                   m3290p       ATmega3290P
                   m32u4        ATmega32U4
                   m48          ATmega48
                   m64          ATmega64
                   m640         ATmega640
                   m644p        ATmega644P
                   m644         ATmega644
                   m645         ATmega645
                   m6450        ATmega6450
                   m649         ATmega649
                   m6490        ATmega6490
                   m8           ATmega8
                   m8515        ATmega8515
                   m8535        ATmega8535
                   m88          ATmega88
                   pwm2         AT90PWM2
                   pwm2b        AT90PWM2B
                   pwm3         AT90PWM3
                   pwm3b        AT90PWM3B
                   t10          ATtiny10
                   t12          ATtiny12 (***)
                   t13          ATtiny13
                   t15          ATtiny15
                   t2313        ATtiny2313
                   t25          ATtiny25
                   t26          ATtiny26
                   t261         ATtiny261
                   t4           ATtiny4
                   t44          ATtiny44
                   t45          ATtiny45
                   t461         ATtiny461
                   t5           ATtiny5
                   t84          ATtiny84
                   t85          ATtiny85
                   t861         ATtiny861

                   t88          ATtiny88
                   t9           ATtiny9
                   ucr2         AT32uca0512
                   usb1286      ATmega1286
                   usb1287      ATmega1287
                   usb162       ATmega162
                   usb646       ATmega647
                   usb647       ATmega647
                   usb82        ATmega82
                   x128a1       ATxmega128A1
                   x128a1d      ATxmega128A1revD
                   x128a3       ATxmega128A3
                   x128a4       ATxmega128A4
                   x16a4        ATxmega16A4
                   x192a1       ATxmega192A1
                   x192a3       ATxmega192A3
                   x256a1       ATxmega256A1
                   x256a3       ATxmega256A3
                   x256a3b      ATxmega256A3B
                   x32a4        ATxmega32A4
                   x64a1        ATxmega64A1
                   x64a3        ATxmega64A3
                   x64a4        ATxmega64A4

                   (*)    The AT90S2323 and ATtiny22 use the same algorithm.

                   (**)   Flash addressing above 128 KB is not supported by
                          all programming hardware.  Known to work are jtag2,
                          stk500v2, and bit-bang programmers.

                   (***)  The ATtiny11 uses the same algorithm, but can only
                          be programmed in high-voltage serial mode.

           -b baudrate
                   Override the RS-232 connection baud rate specified in the
                   respective programmer’s entry of the configuration file.

           -B bitclock
                   Specify the bit clock period for the JTAG interface or the
                   ISP clock (JTAG ICE only).  The value is a floating-point
                   number in microseconds.  The default value of the JTAG ICE
                   results in about 1 microsecond bit clock period, suitable
                   for target MCUs running at 4 MHz clock and above.  Unlike
                   certain parameters in the STK500, the JTAG ICE resets all
                   its parameters to default values when the programming
                   software signs off from the ICE, so for MCUs running at
                   lower clock speeds, this parameter must be specified on the

           -c programmer-id
                   Use the pin configuration specified by the argument.  Pin
                   configurations are read from the config file (see the -C
                   option).  New pin configurations can be easily added or
                   modified through the use of a config file to make avrdude
                   work with different programmers as long as the programmer
                   supports the Atmel AVR serial program method.  You can use
                   the ’default_programmer’ keyword in your ${HOME}/.avrduderc
                   file to assign a default programmer to keep from having to
                   specify this option on every invocation.

           -C config-file
                   Use the specified config file to load configuration data.
                   This file contains all programmer and part definitions that
                   avrdude knows about.  If you have a programmer or part that
                   avrdude does not know about, you can add it to the config
                   file (be sure and submit a patch back to the author so that
                   it can be incorporated for the next version).  See the
                   config file, located at /etc/avrdude.conf, which contains a
                   description of the format.

           -D      Disable auto erase for flash.  When the -U option with
                   flash memory is specified, avrdude will perform a chip
                   erase before starting any of the programming operations,
                   since it generally is a mistake to program the flash
                   without performing an erase first.  This option disables
                   that.  Auto erase is not used for ATxmega devices as these
                   devices can use page erase before writing each page so no
                   explicit chip erase is required.  Note however that any
                   page not affected by the current operation will retain its
                   previous contents.

           -e      Causes a chip erase to be executed.  This will reset the
                   contents of the flash ROM and EEPROM to the value ‘0xff’,
                   and clear all lock bits.  Except for ATxmega devices which
                   can use page erase, it is basically a prerequisite command
                   before the flash ROM can be reprogrammed again.  The only
                   exception would be if the new contents would exclusively
                   cause bits to be programmed from the value ‘1’ to ‘0’.
                   Note that in order to reprogram EERPOM cells, no explicit
                   prior chip erase is required since the MCU provides an
                   auto-erase cycle in that case before programming the cell.

           -E exitspec[,exitspec]
                   By default, avrdude leaves the parallel port in the same
                   state at exit as it has been found at startup.  This option
                   modifies the state of the ‘/RESET’ and ‘Vcc’ lines the
                   parallel port is left at, according to the exitspec
                   arguments provided, as follows:

                   reset    The ‘/RESET’ signal will be left activated at
                            program exit, that is it will be held low, in
                            order to keep the MCU in reset state afterwards.
                            Note in particular that the programming algorithm
                            for the AT90S1200 device mandates that the
                            ‘/RESET’ signal is active before powering up the
                            MCU, so in case an external power supply is used
                            for this MCU type, a previous invocation of
                            avrdude with this option specified is one of the
                            possible ways to guarantee this condition.

                   noreset  The ‘/RESET’ line will be deactivated at program
                            exit, thus allowing the MCU target program to run
                            while the programming hardware remains connected.

                   vcc      This option will leave those parallel port pins
                            active (i. e. high) that can be used to supply
                            ‘Vcc’ power to the MCU.

                   novcc    This option will pull the ‘Vcc’ pins of the
                            parallel port down at program exit.

                   Multiple exitspec arguments can be separated with commas.

           -F      Normally, avrdude tries to verify that the device signature
                   read from the part is reasonable before continuing.  Since
                   it can happen from time to time that a device has a broken
                   (erased or overwritten) device signature but is otherwise
                   operating normally, this options is provided to override
                   the check.  Also, for programmers like the Atmel STK500 and
                   STK600 which can adjust parameters local to the programming
                   tool (independent of an actual connection to a target
                   controller), this option can be used together with -t to
                   continue in terminal mode.

           -i delay
                   For bitbang-type programmers, delay for approximately delay
                   microseconds between each bit state change.  If the host
                   system is very fast, or the target runs off a slow clock
                   (like a 32 kHz crystal, or the 128 kHz internal RC
                   oscillator), this can become necessary to satisfy the
                   requirement that the ISP clock frequency must not be higher
                   than 1/4 of the CPU clock frequency.  This is implemented
                   as a spin-loop delay to allow even for very short delays.
                   On Unix-style operating systems, the spin loop is initially
                   calibrated against a system timer, so the number of
                   microseconds might be rather realistic, assuming a constant
                   system load while avrdude is running.  On Win32 operating
                   systems, a preconfigured number of cycles per microsecond
                   is assumed that might be off a bit for very fast or very
                   slow machines.

           -n      No-write - disables actually writing data to the MCU
                   (useful for debugging avrdude ).

           -O      Perform a RC oscillator run-time calibration according to
                   Atmel application note AVR053.  This is only supported on
                   the STK500v2, AVRISP mkII, and JTAG ICE mkII hardware.
                   Note that the result will be stored in the EEPROM cell at
                   address 0.

           -P port
                   Use port to identify the device to which the programmer is
                   attached.  By default the /dev/ppi0 port is used, but if
                   the programmer type normally connects to the serial port,
                   the /dev/cuaa0 port is the default.  If you need to use a
                   different parallel or serial port, use this option to
                   specify the alternate port name.

                   On Win32 operating systems, the parallel ports are referred
                   to as lpt1 through lpt3, referring to the addresses 0x378,
                   0x278, and 0x3BC, respectively.  If the parallel port can
                   be accessed through a different address, this address can
                   be specified directly, using the common C language notation
                   (i. e., hexadecimal values are prefixed by ‘0x’ ).

                   For the JTAG ICE mkII, if avrdude has been configured with
                   libusb support, port can alternatively be specified as
                   usb[:serialno].  This will cause avrdude to search a JTAG
                   ICE mkII on USB.  If serialno is also specified, it will be
                   matched against the serial number read from any JTAG ICE
                   mkII found on USB.  The match is done after stripping any
                   existing colons from the given serial number, and right-to-
                   left, so only the least significant bytes from the serial
                   number need to be given.

                   As the AVRISP mkII device can only be talked to over USB,
                   the very same method of specifying the port is required

                   For the USB programmer "AVR-Doper" running in HID mode, the
                   port must be specified as avrdoper. Libusb support is
                   required on Unix but not on Windows. For more information
                   about AVR-Doper see

                   For programmers that attach to a serial port using some
                   kind of higher level protocol (as opposed to bit-bang style
                   programmers), port can be specified as net:host:port.  In
                   this case, instead of trying to open a local device, a TCP
                   network connection to (TCP) port on host is established.
                   The remote endpoint is assumed to be a terminal or console
                   server that connects the network stream to a local serial
                   port where the actual programmer has been attached to.  The
                   port is assumed to be properly configured, for example
                   using a transparent 8-bit data connection without parity at
                   115200 Baud for a STK500.  This feature is currently not
                   implemented for Win32 systems.

           -q      Disable (or quell) output of the progress bar while reading
                   or writing to the device.  Specify it a second time for
                   even quieter operation.

           -s      Disable safemode prompting.  When safemode discovers that
                   one or more fuse bits have unintentionally changed, it will
                   prompt for confirmation regarding whether or not it should
                   attempt to recover the fuse bit(s).  Specifying this flag
                   disables the prompt and assumes that the fuse bit(s) should
                   be recovered without asking for confirmation first.

           -t      Tells avrdude to enter the interactive ‘‘terminal’’ mode
                   instead of up- or downloading files.  See below for a
                   detailed description of the terminal mode.

           -u      Disable the safemode fuse bit checks.  Safemode is enabled
                   by default and is intended to prevent unintentional fuse
                   bit changes.  When enabled, safemode will issue a warning
                   if the any fuse bits are found to be different at program
                   exit than they were when avrdude was invoked.  Safemode
                   won’t alter fuse bits itself, but rather will prompt for
                   instructions, unless the terminal is non-interactive, in
                   which case safemode is disabled.  See the -s option to
                   disable safemode prompting.

           -U memtype:op:filename[:format]
                   Perform a memory operation as indicated.  The memtype field
                   specifies the memory type to operate on.  The available
                   memory types are device-dependent, the actual configuration
                   can be viewed with the part command in terminal mode.
                   Typically, a device’s memory configuration at least
                   contains the memory types flash and eeprom.  All memory
                   types currently known are:
                   calibration  One or more bytes of RC oscillator calibration
                   eeprom       The EEPROM of the device.
                   efuse        The extended fuse byte.
                   flash        The flash ROM of the device.
                   fuse         The fuse byte in devices that have only a
                                single fuse byte.
                   hfuse        The high fuse byte.
                   lfuse        The low fuse byte.
                   lock         The lock byte.
                   signature    The three device signature bytes (device ID).
                   fuseN        The fuse bytes of ATxmega devices, N is an
                                integer number for each fuse supported by the
                   application  The application flash area of ATxmega devices.
                   apptable     The application table flash area of ATxmega
                   boot         The boot flash area of ATxmega devices.
                   prodsig      The production signature (calibration) area of
                                ATxmega devices.
                   usersig      The user signature area of ATxmega devices.

                   The op field specifies what operation to perform:

                   r        read device memory and write to the specified file

                   w        read data from the specified file and write to the
                            device memory

                   v        read data from both the device and the specified
                            file and perform a verify

                   The filename field indicates the name of the file to read
                   or write.  The format field is optional and contains the
                   format of the file to read or write.  Format can be one of:

                   i    Intel Hex

                   s    Motorola S-record

                   r    raw binary; little-endian byte order, in the case of
                        the flash ROM data

                   m    immediate; actual byte values specified on the command
                        line, separated by commas or spaces.  This is good for
                        programming fuse bytes without having to create a
                        single-byte file or enter terminal mode.

                   a    auto detect; valid for input only, and only if the
                        input is not provided at stdin.

                   d    decimal; this and the following formats are only valid
                        on output.  They generate one line of output for the
                        respective memory section, forming a comma-separated
                        list of the values.  This can be particularly useful
                        for subsequent processing, like for fuse bit settings.

                   h    hexadecimal; each value will get the string 0x

                   o    octal; each value will get a 0 prepended unless it is
                        less than 8 in which case it gets no prefix.

                   b    binary; each value will get the string 0b prepended.

                   The default is to use auto detection for input files, and
                   raw binary format for output files.  Note that if filename
                   contains a colon, the format field is no longer optional
                   since the filename part following the colon would otherwise
                   be misinterpreted as format.

                   As an abbreviation, the form -U filename is equivalent to
                   specifying -U flash:w:filename:a.  This will only work if
                   filename does not have a colon in it.

           -v      Enable verbose output.

           -V      Disable automatic verify check when uploading data.

           -x extended_param
                   Pass extended_param to the chosen programmer implementation
                   as an extended parameter.  The interpretation of the
                   extended parameter depends on the programmer itself.  See
                   below for a list of programmers accepting extended

           -y      Tells avrdude to use the last four bytes of the connected
                   parts’ EEPROM memory to track the number of times the
                   device has been erased.  When this option is used and the
                   -e flag is specified to generate a chip erase, the previous
                   counter will be saved before the chip erase, it is then
                   incremented, and written back after the erase cycle
                   completes.  Presumably, the device would only be erased
                   just before being programmed, and thus, this can be
                   utilized to give an indication of how many erase-rewrite
                   cycles the part has undergone.  Since the FLASH memory can
                   only endure a finite number of erase-rewrite cycles, one
                   can use this option to track when a part is nearing the
                   limit.  The typical limit for Atmel AVR FLASH is 1000
                   cycles.  Of course, if the application needs the last four
                   bytes of EEPROM memory, this option should not be used.

           -Y cycles
                   Instructs avrdude to initialize the erase-rewrite cycle
                   counter residing at the last four bytes of EEPROM memory to
                   the specified value.  If the application needs the last
                   four bytes of EEPROM memory, this option should not be

   Terminal mode
     In this mode, avrdude only initializes communication with the MCU, and
     then awaits user commands on standard input.  Commands and parameters may
     be abbreviated to the shortest unambiguous form.  Terminal mode provides
     a command history using readline(3), so previously entered command lines
     can be recalled and edited.  The following commands are currently

           dump memtype addr nbytes
                   Read nbytes bytes from the specified memory area, and
                   display them in the usual hexadecimal and ASCII form.

           dump    Continue dumping the memory contents for another nbytes
                   where the previous dump command left off.

           write memtype addr byte1 ... byteN
                   Manually program the respective memory cells, starting at
                   address addr, using the values byte1 through byteN.  This
                   feature is not implemented for bank-addressed memories such
                   as the flash memory of ATMega devices.

           erase   Perform a chip erase.

           send b1 b2 b3 b4
                   Send raw instruction codes to the AVR device.  If you need
                   access to a feature of an AVR part that is not directly
                   supported by avrdude, this command allows you to use it,
                   even though avrdude does not implement the command. When
                   using direct SPI mode, up to 3 bytes can be omitted.

           sig     Display the device signature bytes.

           spi     Enter direct SPI mode.  The pgmled pin acts as slave
                   select.  Only supported on parallel bitbang programmers.

           part    Display the current part settings and parameters.  Includes
                   chip specific information including all memory types
                   supported by the device, read/write timing, etc.

           pgm     Return to programming mode (from direct SPI mode).

           vtarg voltage
                   Set the target’s supply voltage to voltage Volts.  Only
                   supported on the STK500 and STK600 programmer.

           varef [channel] voltage
                   Set the adjustable voltage source to voltage Volts.  This
                   voltage is normally used to drive the target’s Aref input
                   on the STK500.  On the Atmel STK600, two reference voltages
                   are available, which can be selected by the optional
                   channel argument (either 0 or 1).  Only supported on the
                   STK500 and STK600 programmer.

           fosc freq[M|k]
                   Set the master oscillator to freq Hz.  An optional trailing
                   letter M multiplies by 1E6, a trailing letter k by 1E3.
                   Only supported on the STK500 and STK600 programmer.

           fosc off
                   Turn the master oscillator off.  Only supported on the
                   STK500 and STK600 programmer.

           sck period
                   STK500 and STK600 programmer only: Set the SCK clock period
                   to period microseconds.

                   JTAG ICE only: Set the JTAG ICE bit clock period to period
                   microseconds.  Note that unlike STK500 settings, this
                   setting will be reverted to its default value
                   (approximately 1 microsecond) when the programming software
                   signs off from the JTAG ICE.  This parameter can also be
                   used on the JTAG ICE mkII to specify the ISP clock period
                   when operating the ICE in ISP mode.

           parms   STK500 and STK600 programmer only: Display the current
                   voltage and master oscillator parameters.

                   JTAG ICE only: Display the current target supply voltage
                   and JTAG bit clock rate/period.


           help    Give a short on-line summary of the available commands.

           quit    Leave terminal mode and thus avrdude.

   Default Parallel port pin connections
     (these can be changed, see the -c option)
     Pin number   Function
     2-5          Vcc (optional power supply to MCU)
     7            /RESET (to MCU)
     8            SCK (to MCU)
     9            MOSI (to MCU)
     10           MISO (from MCU)
     18-25        GND

   debugWire limitations
     The debugWire protocol is Atmel’s proprietary one-wire (plus ground)
     protocol to allow an in-circuit emulation of the smaller AVR devices,
     using the ‘/RESET’ line.  DebugWire mode is initiated by activating the
     ‘DWEN’ fuse, and then power-cycling the target.  While this mode is
     mainly intended for debugging/emulation, it also offers limited
     programming capabilities.  Effectively, the only memory areas that can be
     read or programmed in this mode are flash ROM and EEPROM.  It is also
     possible to read out the signature.  All other memory areas cannot be
     accessed.  There is no chip erase functionality in debugWire mode;
     instead, while reprogramming the flash ROM, each flash ROM page is erased
     right before updating it.  This is done transparently by the JTAG ICE
     mkII (or AVR Dragon).  The only way back from debugWire mode is to
     initiate a special sequence of commands to the JTAG ICE mkII (or AVR
     Dragon), so the debugWire mode will be temporarily disabled, and the
     target can be accessed using normal ISP programming.  This sequence is
     automatically initiated by using the JTAG ICE mkII or AVR Dragon in ISP
     mode, when they detect that ISP mode cannot be entered.

   Programmers accepting extended parameters
           JTAG ICE mkII

           AVR Dragon
                   When using the JTAG ICE mkII or AVR Dragon in JTAG mode,
                   the following extended parameter is accepted:

                                 Setup the JTAG scan chain for UB units
                                 before, UA units after, BB bits before, and
                                 BA bits after the target AVR, respectively.
                                 Each AVR unit within the chain shifts by 4
                                 bits.  Other JTAG units might require a
                                 different bit shift count.


                                 Override the device code selection by using
                                 VALUE as the device code.  The programmer is
                                 not queried for the list of supported device
                                 codes, and the specified VALUE is not
                                 verified but used directly within the ‘T’
                                 command sent to the programmer.  VALUE can be
                                 specified using the conventional number
                                 notation of the C programming language.

                                 Disables the default checking for block
                                 transfer capability.  Use no_blockmode only
                                 if your AVR910 programmer creates errors
                                 during initial sequence.


                                 The default setup assumes the BusPirate’s CS
                                 output pin connected to the RESET pin on AVR
                                 side. It is however possible to have multiple
                                 AVRs connected to the same BP with MISO, MOSI
                                 and SCK lines common for all of them.  In
                                 such a case one AVR should have its RESET
                                 connected to BusPirate’s CS pin, second AVR’s
                                 RESET connected to BusPirate’s AUX pin and if
                                 your BusPirate has an AUX2 pin (only
                                 available on BusPirate version v1a with
                                 firmware 3.0 or newer) use that to activate
                                 RESET on the third AVR.

                                 It may be a good idea to decouple the
                                 BusPirate and the AVR’s SPI buses from each
                                 other using a 3-state bus buffer. For example
                                 74HC125 or 74HC244 are some good candidates
                                 with the latches driven by the appropriate
                                 reset pin (cs, aux or aux2). Otherwise the
                                 SPI traffic in one active circuit may
                                 interfere with programming the AVR in the
                                 other design.

                                 BusPirate to AVR SPI speed:

                                 0 ..  30 kHz   (default)
                                 1 .. 125 kHz
                                 2 .. 250 kHz
                                 3 ..   1 MHz
                                 4 ..   2 MHz
                                 5 ..   2.6 MHz
                                 6 ..   4 MHz
                                 7 ..   8 MHz

                         ascii   Use ASCII mode even when the firmware
                                 supports BinMode (binary mode).  BinMode is
                                 supported in firmware 2.7 and newer, older
                                 FW’s either don’t have BinMode or their
                                 BinMode is buggy. ASCII mode is slower and
                                 makes the above reset= and speed= parameters


           /dev/ppi0     default device to be used for communication with the
                         programming hardware

                         programmer and parts configuration file

                         programmer and parts configuration file (per-user

           ~/.inputrc    Initialization file for the readline(3) library

                         Schematic of programming hardware


     avrdude: jtagmkII_setparm(): bad response to set parameter command: RSP_FAILED
     avrdude: jtagmkII_getsync(): ISP activation failed, trying debugWire
     avrdude: Target prepared for ISP, signed off.
     avrdude: Please restart avrdude without power-cycling the target.

     If the target AVR has been set up for debugWire mode (i. e. the DWEN fuse
     is programmed), normal ISP connection attempts will fail as the /RESET
     pin is not available.  When using the JTAG ICE mkII in ISP mode, the
     message shown indicates that avrdude has guessed this condition, and
     tried to initiate a debugWire reset to the target.  When successful, this
     will leave the target AVR in a state where it can respond to normal ISP
     communication again (until the next power cycle).  Typically, the same
     command is going to be retried again immediately afterwards, and will
     then succeed connecting to the target using normal ISP communication.


     avr-objcopy(1), ppi(4), readline(3)

     The AVR microcontroller product description can be found at



     Avrdude was written by Brian S. Dean <>.

     This man page by Joerg Wunsch.


     Please report bugs via

     The JTAG ICE programmers currently cannot write to the flash ROM one byte
     at a time.  For that reason, updating the flash ROM from terminal mode
     does not work.

     Page-mode programming the EEPROM through JTAG (i.e. through an -U option)
     requires a prior chip erase.  This is an inherent feature of the way JTAG
     EEPROM programming works.  This also applies to the STK500 and STK600 in
     parallel programming mode.

     The USBasp and USBtinyISP drivers do not offer any option to distinguish
     multiple devices connected simultaneously, so effectively only a single
     device is supported.