A core-dump implementation for PIC18 devices with on-chip Ethernet controller

by Isaac Marino Bavaresco

These routines are an useful tool for debugging complex systems based on Microchip's Ethernet-enabled PIC18 micro-controllers.

They take advantage of the large Ethernet packet buffer to save all the registers, hardware stack and RAM, immediately after an abnormal reset, before they get corrupted by the firmware.

• coredump.asm This file contains a routine that checks whether the reset was abnormal and if yes, copies all the SFRs, hardware stack and RAM to the Ethernet controller packet buffer.
• core-dump-sample.c This file contains an example of how to create a file with the core-dump data for later analysis.
• dumper.cpp This file is a console program that reads the raw core-dump data and generates a human-readable report.

NOTE: In the given sample the core-dump is saved to a file in a file-system. If your board doesn't have a file system, it would be possible to transmit the core-dump by any available interface (serial, for instance) even by the Ehternet controller if you are careful enough for not corrupting the core-dump image in the Ethernet packet buffer.

In the C library startup file (one of the following, depending on your configuration: c018_e.c, c018i_e.c or c018iz_e.c), replace the sequence:

"
...
#pragma code _entry_scn=0x000000
void
_entry (void)
{
_asm goto _startup _endasm}
...
"

"
...
extern void __init0 (void);
#pragma code _entry_scn=0x000000
void
_entry (void)
{
_asm goto __init0 _endasm}
...
"

Probably you will need to add explicitly a linker-script file to your project, and comment the reference to the original "C018*.c".

Code:

• Isaac Marino Bavaresco shares this code: /Techref/member/IMB-yahoo-J86/SimpleRTOS2.htm
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