• Locked Locked
  • Replies 2 replies
  • Subscribers 119 subscribers
  • Views 3676 views
  • Users 0 members are here
Options
Related
How was your experience today?
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Cortex-m4 -Booting and toggling pins

Nicklas Johansson
Note: This was originally posted on 16th October 2012 at http://forums.arm.com

So i got my hands on a stm32f4 - discoveryboard wich contains a cortex-m4? (correct me if i am wrong)

so my first question is, how dose the booting work? or rather, if i have a simple main function doing nothing, how dose the cpu identify this as start?
do i need to do some transfer from the Flash to ram manualy?
if there is any documents or explenation that ivé missed i would be more than glad to get pointed to them again :)

For the second, How do i set pin I/O status? i my mind i belive that there is som underlaying assembler code loading/store differentvalues.
so i gave


asm(
"LDR r8,0x40020c000;" //What i belive to be GPIOA start register
"STR r8,[0x40020c000,0x01];"//Set the first pin in GPIOA to be output?
);


i am a complete noob at this and have never done this befor.
cheers.