[fpc-devel] STM32F407 fun

[Andrew Haines]

Hi,

I've been trying to get a very simple program to run on my discovery 
board that I've had for a while(STM32F407VG). Using st-util with gdb I 
managed to make some progress.

I've been using the code in fpc for STM32F429 since it's pretty similar. 
My first problem was that the stackpointer was too high. The STM32F407VG 
has 64kb less memory than the STM32F429. I added a define in 
compiler/arm/cpuinfo.pas with the correct info and had it use the 
STM32F429 unit. That fixed my first problem.

The next/current problem is in CommonInit in system.
SynchronizeTimeoutEvent:=RtlEventCreate;

RtlEventCreate has:
result:=currenttm.rtleventcreate();
This produces the assembly:
0x8007e08 <SYSTEM_$$_RTLEVENTCREATE$$PRTLEVENT> push   {lr}
(gdb) i registers pc
pc             0x8007e0a        0x8007e0a 
<SYSTEM_$$_RTLEVENTCREATE$$PRTLEVENT+2>

0x8007e0a <SYSTEM_$$_RTLEVENTCREATE$$PRTLEVENT+2> ldr    r0, [pc, #8]    
; (0x8007e14 <SYSTEM_$$_RTLEVENTCREATE$$PRTLEVENT+12>)
(gdb) i registers r0
r0             0x20001dc0       536878528  // the address 1dc0 seems 
reasonable. Location of currenttm+rtleventcreate?

0x8007e0c <SYSTEM_$$_RTLEVENTCREATE$$PRTLEVENT+4> ldr    r0, [r0, #0] 
(gdb) i registers r0
r0             0x0      0

0x8007e0e <SYSTEM_$$_RTLEVENTCREATE$$PRTLEVENT+6> blx    r0

For the last instruction r0 is nil. This causes the default interrupt 
handler to be called which loops forever.

backtrace is:
(gdb) bt
#0  0x08007e0e in SYSTEM_$$_RTLEVENTCREATE$$PRTLEVENT ()
#1  0x0800ce5e in CLASSES_$$_COMMONINIT ()
#2  0x08012886 in CLASSES_$$_init ()
#3  0x08007a5c in fpc_initializeunits ()
#4  0x08000294 in main () at blinky.lpr:48

I compiled the crosscompiler with:
make clean  buildbase  CROSSINSTALL=1 CROSSOPT="-XParm-none-eabi-" 
OS_TARGET=embedded CPU_TARGET=arm SUBARCH=armv7em

the program is compiled with
-Oparmv7em
-WpSTM32F407VG

I'm guessing there is some define I have to use and everything will 
start working :)

Where do I go from here?

Thanks in advance,

Andrew Haines