Linux/AM3352: UART CTS and RTS as GPIO

Borja Gomez4

Part Number: AM3352

Tool/software: Linux

Hello!

I'm working with an AM335x based custom board. The application of the board needs to use too many GPIOS. So I would like to know if it is possible to use UARTx_CTS and UARTx_RTS as a GPIOs when we are enabling UARTx for the processor in .dts file?

I have not found this information in the datasheet and previous theads do not answer this question:

e2e.ti.com/.../1976662

Thank you in advance

Borja

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Yes, of course you can. What you need to do is pinmux these pins to their GPIO mode and make sure they are not pinmuxed to UART mode elsewhere.

0 Borja Gomez4 over 9 years ago in reply to Biser Gatchev-XID

Prodigy 70 points

Dear Biser,

Thank you for your fast repply.

In this app I have to use one of the UARTs for RS485 comms. I have read in previous forum that the RST signal could a source of problems. Depending of the driver used for this RS485 comm (8250 / Serial) the transmit Enable signal of the RS485 tranceiver needs to be a GPIO or a RS485. I do not decide the way in whitch i will do that, so I would like to cover both posibilities. Due to the high neccesity of GPIOs of our application (I do not want to use an extra GPIO), the best way to do this is to connect the RTS pin to the transceiver transmit enable signal and then configure the RST signal as UART or as a GPIO depending of the driver in use. According to your repply this should be possible. Is not?

Thank you in advance

Borja Gómez

0 Biser Gatchev-XID over 9 years ago in reply to Borja Gomez4

TI__Guru**** 393215 points

Yes, this is possible. You will be able to configure the pin as required by the driver.

0 Borja Gomez4 over 9 years ago in reply to Biser Gatchev-XID

Prodigy 70 points

Ok, Thank you

Borja

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Linux/AM3352: UART CTS and RTS as GPIO