Jumping to Reset_Handler?

sima · ‎2009-03-08

Posted on March 08, 2009 at 19:29

sima · ‎2011-05-17

Posted on May 17, 2011 at 13:05

Hello again :D

I'm compiling the QuickStart_STM32 exemple provided in Ride7 and looking at the generated memory map.

If i start debugging and look at Memory View window the Reset Handler address looks like 0x0800 01E5.

But in the Disassembly View window Reset_Handler has the address 0x0800 01E4.

I have seen this on other examples too.

What is going on, why does the address diff 1 byte address?

(se picture)

16-32micros · ‎2011-05-17

Posted on May 17, 2011 at 13:05

Hi sima,

This behavior is correct and there is no issues there. In fact this is how Cortex-M3 is decoding the address and always the PC ( program counter) should have the LSB equal to 1, that means it is executing in Thumb2 state, if it moves accidentally to 0 , so in you case to xxxxxxE4 , it would create a INVSTATE fault because T bit is 0 (ARM state).

for more details refer to

http://infocenter.arm.com/help/topic/com.arm.doc.ddi0337e/DDI0337E_cortex_m3_r1p1_trm.pdf

. Page 96/384 ( Note ) & Page 64/384 ( ''T'' bit definition )

Cheers,

STOne-32.

[ This message was edited by: STOne-32 on 09-03-2009 00:06 ]