Device Electronic signature and ID codes

[ryan2399]

Posted on November 18, 2008 at 20:21

Device Electronic signature and ID codes

[ryan2399]

Posted on May 17, 2011 at 12:52

Firstly... I'm curious why the RAM size register has been removed from the latest reference manual (section 25). Can we no longer rely on this register?

Second... I'm having trouble reading the ID code located at 0xE0042000. It works like a charm when I'm executing my code using the debugger. When executing without a debugger all I get back is 0x00000000 (instead of 0x20006410 I get during debugging). Obviously this is a little hard to debug :-). What am I missing here? I need to enable some register/peripheral to read this when not debugging?

[ryan2399]

Posted on May 17, 2011 at 12:52

Thanks that does explain it.

I really don't understand removing the RAM size register so arbitrarily though.

It doesn't really simplify software design... now I need to do RAM sizing. Before I could just read a register.

[16-32micros]

Posted on May 17, 2011 at 12:52

Dear ryan, all,

RAM register size is no more relevant and not existing anymore in our STM32 devices silicon. This is to simplify the software design and to rely only to Flash size which is most important than RAM.

Regarding, the ID code located at 0xE0042000. Refer to STM32 Errata

http://www.st.com/mcu/modules.php?name=mcu&file=familiesdocs&FAM=110#Errata Sheet

:

Debug registers cannot be read by user software

The DBGMCU_IDCODE and DBGMCU_CR debug registers are accessible only in debug mode (not accessible by the user software). When these registers are read in user mode, the returned value is 0x00.

Hope this helps you. Cheers,

ST1.

[ This message was edited by: STOne-32 on 14-11-2008 16:15 ]