May 1, 2025
STM32H743 Nucleo board -- LED and buttons
In other words, important things we can learn from the schematic.
Crystals
There is a 25 Mhz crystal oscillator next to the F723 in the ST-Link Section.
There is an unmarked LSE crystal (the schematic shows 32.768 Khz.
The HSE crystal is not present!
There is another 25 Mhz crystal (X4) next to the SMSC 8742A Phy chip.
So it seems that the CPU clock needs to be derived from the 32.768 kHz crystal.
Buttons
We have a reset button -- no surprises there.
There is also a blue "user" button connected to PC13.
The schematic shows an optional jumper to connect it to PA0.
LED
There is a power LED that lets you know if you have 5 volt power, wherever it
might be coming from
There is a bicolor red/green LED controlled by the F723 ST-Link chip.
We have 3 user LED:
- LD1 - Green - PB0 (PA5 via alternate jumper)
- LD2 - Orange (yellow) - PB1
- LD3 - Red - PB14
There are two USB led
- VBUS OK (green)
- VBUS OVCR (red)
USB
- PA11 = USB_FS_N
- PA12 = USB_FS_P
console UART
These signals are STLK_VCP_RX/TX, these come from:
- T_VCP_TX = USART3_TX (PD8)
- T_VCP_RX = USART3_RX (PD9)
Feedback? Questions?
Drop me a line!
Tom's Computer Info / tom@mmto.org