December 19, 2023

STM32H747I-DISCO "Discovery kit with STM32H747XI MCU" -- on board LED

First a minor disappointment. The bicolor LED is connected to the ST-Link processor, and we won't be able to fool with it. It is not a fancy multicolor device, it is a pair of red and green LED in a single package, wired in reverse directions -- so you can get red or green.

But we do have four LED we can manipulate. They are on GPIO "I" as follows: 

PI2 -- led 1  - green
PI3 -- led 2  - orange
PI4 -- led 3  - red
PI5 -- led 4  - blue
They are fed 3.3 volts and you pull the GPIO down (open collector) to turn them on.

What about those GPIO ?

They are described in section 12 of the RM (page 568). They each have 16 bits, and we have 11 of them (A,B,C,D,E,F,G,H,I,J,K). Of course many bits are dedicated to special purposes, and we don't have 176 pins (on this board anyway).

Section 2.3.2 (page 135) of the RM gives the memory map, and Table 7 shows the base addresses of various registers, including the GPIO, as follows: 

GPIOA - 0x5802_0000
GPIOB - 0x5802_0400
GPIOC - 0x5802_0800
GPIOD - 0x5802_0C00
GPIOE - 0x5802_1000
GPIOF - 0x5802_1400
GPIOG - 0x5802_1800
GPIOH - 0x5802_1c00
GPIOI - 0x5802_2000
GPIOJ - 0x5802_2400
GPIOK - 0x5802_2800
So we want 0x5802_2000 to get at those LED.
Feedback? Questions? Drop me a line!

Tom's Computer Info / [email protected]