STM32F103RDT6 Pin details

[Mom.1]

Hi,

I am using STM32F103RDT6 for my project. I need only two seperate uart lines and 2 Gpios for to connect 2 RS485 transceivers.

1. I need TX ,RX pin only. So what about the CTS & RTS pin. can I make that as float?
2. There is 2 boot pins in the IC. how I configure those pins?
3. Is any pull up /pull down needed for the unused pins or can I make that float?

Kindly reply

Warm regards,

Monisha OM

[berendi]

1. CTS and RTS are used only if they are explicitly enabled, otherwise they can be used for other (GPIO) purposes or left unconnected. See the USART Hardware flow control chapter in the reference manual.
2. Boot pin functionality is described in the Boot configuration chapter of the reference manual. You'll need Main Flash memory mode for normal operation, and maybe System memory if you plan to use the DFU or serial bootloader.
3. Unused pins can be left unconnected. It's recommended to activate the internal pullups or pulldowns on all unconnected pins. See AN2586 Getting started with STM32F10xxx hardware development

[Mom.1]

Hi,

Thank you for your response.

I have one more doubt.

What is the function of tamper_RTC pin. As in my case, I am not using any RTC. so can I make that pin float or use as GPIO? Do that pin have any default function.

Warm regards,

Monisha OM

[Tesla DeLorean]

PC13 is in the low power domain, you can use it as an input, or as a low current driver.

This is a datasheet, you'd do well to review it, saves having doubts. https://www.st.com/resource/en/datasheet/stm32f103rd.pdf

[berendi]

No GPIO pins have a default function after reset, only the debug interface (JTAG/SDWIO) pins.

Any other special function has to be explicitly activated first in the respective peripheral.

The debug pins have their internal pullups/pulldowns activated at reset.