TM4C1231D5PZ: Fail Safe Pins

Akash S

Part Number: TM4C1231D5PZ

Hi,

We are using TM4C1231D5PZ for an RS485 based application.

The RS485 tranceiver operates at 5V and hence the receiver output is at 5V. Can we connect this signal directly to the UART_RXD pins of the controller?

over 3 years ago

0 Chester Gillon over 3 years ago

Guru 92251 points

Akash S said:
Can we connect this signal directly to the UART_RXD pins of the controller?

Does the following from the Tiva C Series TM4C1231D5PZ Microcontroller Data Sheet datasheet (Rev. E) answer your question?

0 Ralph Jacobi over 3 years ago

TI__Guru*** 135355 points

Hello Akash,

You can depending on how much risk you want to manage. 5.5V is the absolute maximum rating beyond which pins may be damaged. So even with a 5V tolerant pin, we recommend the use of level shifters. If you have a 5% tolerance on your 5V supply, that could push it up to 5.25V without even accounting for noise or spikes. So you would need to evaluate your system and assess long term risk.

My official recommendation will be to minimize risk and employ level shifters.

Best Regards,

Ralph Jacobi

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TM4C1231D5PZ: Fail Safe Pins