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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 -logfile] [-n] [-O] [-P port] [-q] [-s]
[-t] [-u] [-U memtype:op:filename:filefmt] [-v] [-x extended_param] [-V]


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 (mkI, mkII and 3, the latter two 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.

If you happen to have a Linux system with at least 4 hardware GPIOs available (like almost
all embedded Linux boards) you can do without any additional hardware - just connect them to
the MOSI, MISO, RESET and SCK pins on the AVR and use the linuxgpio programmer type. It
bitbangs the lines using the Linux sysfs GPIO interface. Of course, care should be taken
about voltage level compatibility. Also, although not strictrly required, it is strongly
advisable to protect the GPIO pins from overcurrent situations in some way. The simplest
would be to just put some resistors in series or better yet use a 3-state buffer driver like
the 74HC244. Have a look at http://kolev.info/avrdude-linuxgpio for a more detailed tutorial
about using this programmer type.

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).

Wiring boards are supported, utilizing STK500 V2.x protocol, but a simple DTR/RTS toggle is
used to set the boards into programming mode. The programmer type is ``wiring''.

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 (mkI, mkII, and 3) 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). JTAGICE3 also supports all of JTAG, debugWIRE, and ISP mode. 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). For
ATxmega devices, the JTAGICE3 is supported in PDI mode.

Atmel-ICE (ARM/AVR) is supported in all modes (JTAG, PDI for Xmega, debugWIRE, ISP).

Atmel's XplainedPro boards, using the EDBG protocol (CMSIS-DAP compatible), are supported
using the "jtag3" programmer type.

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 avrftdi, USBasp ISP and USBtinyISP adapters are also supported, provided avrdude has
been compiled with libusb support. USBasp ISP and USBtinyISP both feature simple firmware-
only USB implementations, running on an ATmega8 (or ATmega88), or ATtiny2313, respectively.
If libftdi has has been compiled in avrdude, the avrftdi device adds support for many
programmers using FTDI's 2232C/D/H and 4232H parts running in MPSSE mode, which hard-codes
(in the chip) SCK to bit 1, MOSI to bit 2, and MISO to bit 3. Reset is usually bit 4.

The Atmel DFU bootloader is supported in both, FLIP protocol version 1 (AT90USB* and
ATmega*U* devices), as well as version 2 (Xmega devices). See below for some hints about
FLIP version 1 protocol behaviour.

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.

Provided libelf(3) was present when compiling avrdude, the input file can also be the final
ELF file as produced by the linker. The appropriate ELF section(s) will be examined,
according to the memory area to write to.

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 well.

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. For currently supported MCU types use ? as partno, this
will print a list of partno ids and official part names on the terminal. (Both
can be used with the -p option.)

Following parts need special attention:

AT90S1200 The ISP programming protocol of the AT90S1200 differs in subtle
ways from that of other AVRs. Thus, not all programmers support
this device. Known to work are all direct bitbang programmers,
and all programmers talking the STK500v2 protocol.

AT90S2343 The AT90S2323 and ATtiny22 use the same algorithm.

ATmega2560, ATmega2561
Flash addressing above 128 KB is not supported by all programming
hardware. Known to work are jtag2, stk500v2, and bit-bang

ATtiny11 The ATtiny11 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. Alternatively,
the value might be suffixed with "Hz", "kHz", or "MHz", in order to specify
the bit clock frequency, rather than a period. 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 command-line. You can use the
'default_bitclock' keyword in your ${HOME}/.avrduderc file to assign a default
value to keep from having to specify this option on every invocation.

-c programmer-id
Use the programmer specified by the argument. Programmers and their 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. A full list of all supported programmers is output to the
terminal by using ? as programmer-id.

-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.

If config-file is written as +filename then this file is read after the system
wide and user configuration files. This can be used to add entries to the
configuration without patching your system wide configuration file. It can be
used several times, the files are read in same order as given on the command

-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

-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

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

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.

d_high This option will leave the 8 data pins on the parallel port active.
(i. e. high)

d_low This option will leave the 8 data pins on the parallel port inactive.
(i. e. low)

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

-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.

-l logfile
Use logfile rather than stderr for diagnostics output. Note that initial
diagnostic messages (during option parsing) are still written to stderr

-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 and JTAGICE3, if avrdude has been configured with libusb
support, port can alternatively be specified as usb[:serialno]. This will
cause avrdude to search the programmer 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 there.

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 the USBtinyISP, which is a simplicistic device not implementing serial
numbers, multiple devices can be distinguished by their location in the USB
hierarchy. See the the respective Troubleshooting entry in the detailed
documentation for examples.

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.

-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.

If one of the configuration files has a line
default_safemode = no;
safemode is disabled by default. The -u option's effect is negated in that
case, i. e. it enables safemode.

Safemode is always disabled for AVR32, Xmega and TPI devices.

-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 data.
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 device.
application The application flash area of ATxmega devices.
apptable The application table flash area of ATxmega devices.
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

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

e ELF (Executable and Linkable Format)

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 prepended.

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.

When reading any kind of flash memory area (including the various sub-areas in
Xmega devices), the resulting output file will be truncated to not contain
trailing 0xFF bytes which indicate unprogrammed (erased) memory. Thus, if the
entire memory is unprogrammed, this will result in an output file that has no
contents at all.

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

-v Enable verbose output. More -v options increase verbosity level.

-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

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

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

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

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,
JTAGICE3, and Atmel-ICE 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

verbose [level]
Change (when level is provided), or display the verbosity level. The initial
verbosity level is controlled by the number of -v options given on the


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.

FLIP version 1 idiosyncrasies
Bootloaders using the FLIP protocol version 1 experience some very specific behaviour.

These bootloaders have no option to access memory areas other than Flash and EEPROM.

When the bootloader is started, it enters a security mode where the only acceptable access
is to query the device configuration parameters (which are used for the signature on AVR
devices). The only way to leave this mode is a chip erase. As a chip erase is normally
implied by the -U option when reprogramming the flash, this peculiarity might not be very
obvious immediately.

Sometimes, a bootloader with security mode already disabled seems to no longer respond with
sensible configuration data, but only 0xFF for all queries. As these queries are used to
obtain the equivalent of a signature, avrdude can only continue in that situation by forcing
the signature check to be overridden with the -F option.

A chip erase might leave the EEPROM unerased, at least on some versions of the bootloader.

Programmers accepting extended parameters



AVR Dragon
When using the JTAG ICE mkII, JTAGICE3, Atmel-ICE 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.

The SPI speed for the Bus Pirate's binary SPI mode:

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

Sets the SPI speed and uses the Bus Pirate's binary "raw-wire"

0 .. 5 kHz
1 .. 50 kHz
2 .. 100 kHz (Firmware v4.2+ only)
3 .. 400 kHz (v4.2+)

The only advantage of the "raw-wire" mode is the different SPI
frequencies available. Paged writing is not implemented in this

ascii Attempt to 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=, spifreq=
and rawfreq= parameters unavailable. Be aware that ASCII mode is
not guaranteed to work with newer firmware versions, and is
retained only to maintain compatibility with older firmware

Firmware versions 5.10 and newer support a binary mode SPI
command that enables whole pages to be written to AVR flash
memory at once, resulting in a significant write speed increase.
If use of this mode is not desirable for some reason, this
option disables it.

Newer firmware versions support in binary mode SPI command some
AVR Extended Commands. Using the "Bulk Memory Read from Flash"
results in a significant read speed increase. If use of this
mode is not desirable for some reason, this option disables it.

This sets the AUX pin to output a frequency of n kHz. Connecting
the AUX pin to the XTAL1 pin of your MCU, you can provide it a
clock, for example when it needs an external clock because of
wrong fuses settings. Make sure the CPU frequency is at least
four times the SPI frequency.

This sets the serial receive timeout to the given value. The
timeout happens every time avrdude waits for the BusPirate
prompt. Especially in ascii mode this happens very often, so
setting a smaller value can speed up programming a lot. The
default value is 100ms. Using 10ms might work in most cases.

Wiring When using the Wiring programmer type, the following optional extended
parameter is accepted:

After performing the port open phase, AVRDUDE will wait/snooze
for snooze milliseconds before continuing to the protocol sync
phase. No toggling of DTR/RTS is performed if snooze is greater
than 0.

Connection to the PICkit2 programmer:

(AVR) (PICkit2)
VDD - VDD Target (2) -- possibly optional if AVR self powered
GND - GND (3)
MISO - PGD (4)
SCLK - PDC (5)
MOSI - AUX (6)

Extended commandline parameters:

Sets the SPI clocking rate in Hz (default is 100kHz).
Alternately the -B or -i options can be used to set the period.

Sets the timeout for USB reads and writes in milliseconds
(default is 1500 ms).

Use avrdude online using onworks.net services

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