ice-gdb(1)ice-gdb(1)NAMEice-gdb - JTAG ICE frontend for avr-gdb
ice-insight - JTAG ICE frontend for avr-insight
SYNOPSIS
ice-gdb/ice-insight [--debugger debugger] [--capture] [--ignore-intr]
[--external] [gdb_arguments]
DESCRIPTIONice-gdb (respectively ice-insight) starts avr-gdb (respectively avr-
insight) and avarice to do on-chip debugging on Atmel AVR processors
using their JTAG-based on-chip debug facilities, via the Atmel JTAG ICE
pod.
The executable for the program being debugged is downloaded to the pro‐
cessor unless the --capture option is specified. A number of extra com‐
mands are available within gdb when started, see their description in
NEW GDB COMMANDS below. Restrictions on debugging with the JTAG ICE pod
are discussed in more detail in DEBUGGING WITH JTAG ICE below.
The arguments passed to avarice include the value of the AVARICE_ARGS
environment variable. This is typically used to specify the serial port
to which the JTAG ICE pod is connected by setting AVARICE_ARGS to "-j
<serial port name>".
OPTIONS--debugger debugger_command
Specify a different debugger than avr-gdb (or avr-insight). This
other debugger should behave similarly to gdb.
--capture
Don't download the executable being debugged to the mote, just
interrupt the current program and assume that it matches the
executable passed to ice-gdb. This is similar to "attaching" to
a running program within gdb.
--ignore-intr
Pass the --ignore-intr option to avarice. The single-step com‐
mands in gdb (s, n) will then "step over" interrupt handlers
(i.e., if an interrupt occurs, execution will resume for the
duration of the interrupt).
--external
Do not start avarice. Instead, avr-gdb will attempt to connect
to an already running avarice on port localhost:6423.
NEW GDB COMMANDS
ice-restart
Restart avarice.
ice-load filename
Download executable filename to the Atmel processor and start
debugging it (this replaces the gdb load command).
target-ice
Connect to a copy of avarice running on port localhost:6423.
DEBUGGING WITH JTAG ICE
The JTAG ICE debugging environment has a few restrictions and changes:
· No "soft" breakpoints, and only three hardware breakpoints. The
break command sets hardware breakpoints. The easiest way to deal
with this restriction is to enable and disable breakpoints as
needed.
· Two 1-byte hardware watchpoints (but each hardware watchpoint takes
away one hardware breakpoint). If you set a watchpoint on a vari‐
able which takes more than one byte, execution will be abysmally
slow. Instead it is better to do the following:
watch *(char *)&myvariable
which watches the least significant byte of myvariable.
· The Atmel AVR processors have a Harvard architecture (separate code
and data buses). To distinguish data address 0 from code address 0,
avr-gdb adds 0x800000 to all data addresses. Bear this in mind when
examining printed pointers, or when passing absolute addresses to
gdb commands.
ENVIRONMENT
AVARICE_ARGS
Extra arguments to pass to avarice at startup.
SEE ALSOgdb(1), insight(1).
BUGS
On Windows, the ice-gdb and ice-insight commands only work in the cyg‐
win environment. They do not work with the mingw environment.
August 22, 2003 ice-gdb(1)
