CCS/TMS570LS0432: How to connect 2 TMS570LS04 pi by their GPIO Pins?

user5342390

Prodigy 200 points

Part Number: TMS570LS0432

Tool/software: Code Composer Studio

Hi,

I need to connect two Launchpad TMS570LS04 through a GPIO.

One is as an input and the other as an output (I use HET pins).

It works fine if I do it on the same MCU. But when I try to interface the two MCUs it doesn't work....

I connected the ground well between the two cards

Can someone help me? Thank you.

Maxime

over 7 years ago

0 QJ Wang over 7 years ago

TI__Guru**** 197356 points

What do you mean "it doesn't work"? The NHET GIO doesn't support input interrupt. Please don't toggle the pin fast in the transmitting side.
1. In TX side, configure 1 NHET pin (for example NHET0) as output, then set NHET0 (HETDSET)
2. In RX side, configure 1 NHET pin (for example NHET0, connect NHET0 on 2 boards together with a wire) as input, then read NHET0 HETDIN register, the bit 0 should be set.

0 user5342390 over 7 years ago in reply to QJ Wang

Prodigy 200 points

Thank you for your answer.

The problem is the following:

when I set my Tx to "1" and the input and output are not connected, the output Tx is at 3.3v.

when I set my Tx to "1" and the input and output are connected, the voltage drops to 0.2v, and therefore Rx cannot read the "1"...

0 QJ Wang over 7 years ago in reply to user5342390

TI__Guru**** 197356 points

Is NHET pin in receiver side configured as input? Any pull down resistors on the board for this pin? Is the internal pulldown enabled?

0 user5342390 over 7 years ago in reply to QJ Wang

Prodigy 200 points

Thanks, it works now.

It was just a pull-up/pull-down problem.

Thanks for your help!

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CCS/TMS570LS0432: How to connect 2 TMS570LS04 pi by their GPIO Pins?