MSPM0L1304: UART Communication Issue Between Two Devices

Tool/software:

Hi all,

I'm working on getting UART communication running between two devices:

• Device1: MSPM0 microcontroller

• Device2: Teensy 4.0

Both devices are configured for 115200 baud, 8 data bits, no parity, 1 stop bit (8N1).

However, I’m encountering some strange behavior:

• If bytes from Device2 (Teensy 4.0) are sent rapidly (with no delay between them), they sometimes get merged or misinterpreted on Device1 (MSPM0). There's a mostly consistent but incorrect mapping of the received bytes — the same garbled byte(s) appear for the same tightly packed message.

• If I add a 1 ms delay between each byte sent from Device2, the received data on Device1 becomes a 1:1 mapping (one byte received per one sent) — but the received values are always 0xFF or 0xFE, regardless of what was sent.

• Sending from Device1 to Device2 results in each single byte being received as two bytes: 0x00 0x00 on Device2, even with a 1 ms delay between each byte.

Has anyone run into this kind of issue before?

Any suggestions on what might be causing this would be greatly appreciated.

Thanks!