e109e2e3e8
* Debug: remove lxml dependency, pickle SVD tree for faster processing. * Debug: remove unused import in svd.py
85 lines
3.3 KiB
Markdown
85 lines
3.3 KiB
Markdown
PyCortexMDebug
|
|
==============
|
|
|
|
*A set of GDB/Python-based utilities to make life debugging ARM Cortex-M processors a bit easier*
|
|
|
|
It will consist of several modules which will hopefully become integrated as they evolve. Presently, there is only one:
|
|
|
|
## SVD
|
|
ARM defines an SVD (System View Description) file format in its CMSIS
|
|
standard as a means for Cortex-M-based chip manufacturers to provide a
|
|
common description of peripherals, registers, and register fields. You
|
|
can download SVD files for different manufacturers
|
|
[here](http://www.arm.com/products/processors/cortex-m/cortex-microcontroller-software-interface-standard.php).
|
|
|
|
My implementation so far has only tested STM32 chips but should hold for others. If others are like those from ST,
|
|
expect plenty of errors in the file. Like GPIOA having a register named GPIOB_OSPEEDR and lots of 16-bit registers
|
|
that are listed as 32!
|
|
|
|
The implementation consists of two components -- An xml parser module (pysvd) and a GDB file (gdb_svd).
|
|
I haven't yet worked out a perfect workflow for this, though it's quite easy to use when
|
|
you already tend to have a GDB initialization file for starting up OpenOCD and the like.
|
|
However your workflow works, just make sure to, in GDB:
|
|
|
|
source gdb_svd.py
|
|
svd_load [your_svd_file].svd
|
|
|
|
These files can be huge so it might take a second or two. Anyways, after that, you can do
|
|
|
|
svd
|
|
|
|
to list available peripherals with descriptions. Or you can do
|
|
|
|
svd [some_peripheral_name]
|
|
|
|
to see all of the registers (with their values) for a given peripheral. For more details, run
|
|
|
|
svd [some_peripheral_name] [some_register_name]
|
|
|
|
to see all of the field values with descriptions.
|
|
|
|
You can add format modifiers like:
|
|
|
|
* `svd/x` will display values in hex
|
|
* `svd/o` will display values in octal
|
|
* `svd/t` or `svd/b` will display values in binary
|
|
* `svd/a` will display values in hex and try to resolve symbols from the values
|
|
|
|
All field values are displayed at the correct lengths as provided by the SVD files.
|
|
Also, tab completion exists for nearly everything! When in doubt, run `svd help`.
|
|
|
|
### TODO
|
|
|
|
Enable writing to registers and individual fields
|
|
|
|
### Bugs
|
|
|
|
There are probably a few. All planning, writing, and testing of this was done in an afternoon. There may be
|
|
some oddities in working with non-STM32 parts. I'll play with this when I start working with other
|
|
controllers again. If something's giving you trouble, describe the problem and it shall be fixed.
|
|
|
|
## DWT
|
|
The ARM Data Watchpoint and Trace Unit (DWT) offers data watchpoints and a series of gated cycle counters. For now,
|
|
I only support the raw cycle counter but facilities are in place to make use of others. As this is independent of the
|
|
specific device under test, commands are simple and you can configure a clock speed to get real time values from
|
|
counters.
|
|
|
|
dwt configclk 48000000
|
|
|
|
will set the current core clock speed. Then
|
|
|
|
dwt cyccnt reset
|
|
dwt cyccnt enable
|
|
|
|
will reset and start the cycle counter. At any point
|
|
|
|
dwt cycnt
|
|
|
|
will then indicate the number of cycles and amount of time that has passed.
|
|
|
|
## ITM/ETM support
|
|
|
|
This is not implemented yet. I want to have more complete support for some of the nicer debug and trace features
|
|
on Cortex-M processors. Parts of this will probably be dependent on OpenOCD and possibly on specific interfaces.
|
|
I'll try to avoid this where possible but can't make any promises.
|