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Diffstat (limited to 'docs/stm32f1.md')
| -rw-r--r-- | docs/stm32f1.md | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/docs/stm32f1.md b/docs/stm32f1.md index 04868ec6..e65113fd 100644 --- a/docs/stm32f1.md +++ b/docs/stm32f1.md @@ -20,10 +20,14 @@ STM32F1 port. Fixed pins ========== -The UART used for communication with the host is fixed to pins PA9 (TX) and PA10 -(RX). SWD pins (PA13/PA14) are enabled for debugging and cannot be used for any -I/O. SPI uses pins PB13/PB14/PB15, but the pins can be used as general I/O if -SPI is not used. +When using serial, the UART used for communication with the host is +fixed to pins PA9 (TX) and PA10 (RX). When using USB, the PA11 (D-) +and PA12 (D+) pins are reserved. The USB code assumes that PA12 (D+) +has a fixed pullup resistor attached to it. + +SWD pins (PA13/PA14) are enabled for debugging and cannot be used for +any I/O. SPI uses pins PB13/PB14/PB15, but the pins can be used as +general I/O if SPI is not used. Digital I/O =========== |