Dumping Variables On Demand; Running Espcoredump.py - Espressif ESP32-S2 Programming Manual

Chapter 4. API Guides
broken with error message at the first ROM function. To overcome this issue you can use ROM ELF provided by
Espressif (https://dl.espressif.com/dl/esp32s2_rom.elf) and pass it to 'espcoredump.py'.

4.9.6 Dumping variables on demand

Sometimes you want to read the last value of a variable to understand the root cause of a crash. Core dump supports
retrieving variable data over GDB by attributing special notations declared variables.
Supported notations and RAM regions
• COREDUMP_DRAM_ATTR places variable into DRAM area which will be included into dump.
• COREDUMP_RTC_ATTR places variable into RTC area which will be included into dump.
• COREDUMP_RTC_FAST_ATTR places variable into RTC_FAST area which will be included into dump.
Example
1. In Project Configuration
2. In your project, create a global variable in DRAM area as such as:
// uint8_t global_var;
COREDUMP_DRAM_ATTR uint8_t global_var;
3. In main application, set the variable to any value and assert(0) to cause a crash.
global_var = 25;
assert(0);
4. Build, flash and run the application on a target device and wait for the dumping information.
5. Run the command below to start core dumping in GDB, where PORT is the device USB port:
espcoredump.py -p PORT dbg_corefile <path/to/elf>
6. In GDB shell, type p global_var to get the variable content:
(gdb) p global_var
$1 = 25 '\031'

4.9.7 Running espcoredump.py

Generic command syntax: espcoredump.py [options] command [args]
Script Options
–chip {auto,esp32,esp32s2,esp32s3,esp32c3} Target chip type. Default value is "auto"
--port PORT, -p PORT Serial port device. Either"chip"or"port"need to be
--baud BAUD, -b BAUD Serial port baud rate used when flashing/reading
--gdb-timeout-sec GDB_TIMEOUT_SEC Overwrite the default internal delay
Commands dbg_corefile Starts GDB debugging session with specified corefile
info_corefile Print core dump info from file
Command Arguments
--debug DEBUG, -d DEBUG Log level (0..3)
--gdb GDB, -g GDB Path to gdb
--core CORE, -c CORE Path to core dump file (if skipped core dump will be
Espressif Systems
Menu, enable COREDUMP TO
specified to determine the port when you have multi-target
connected at the same time.
for gdb responses
read from flash)
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FLASH, then save and exit.
Release v4.4