Operation timeout when being sent 64-byte packet.

[alecct-exi]

I'm currently using serialport-rs for a host-side application communicating to an embedded device and I'm unsure on whether the cause of my bug is my host-side configuration or something I'm doing on the device side (in which case this question will be irrelevant).

When I write packets from the device that are less than 64 bytes long the host receives them fine, with the read function returning Ok(n) where n is the correct number of bytes I sent from the device.
The problem is when I try to write a whole 64-byte packet from the device, the read function always times out returning a timeout message wrapped in the Err return type, no matter how long I set the timeout to be in the serial port's configuration, nor when setting a significant delay before reading. This issue remains when passing the read function an array(or vector) to read into which has a size greater than 64 bytes.

Does anyone have a suggestion for what I might be doing wrong or might it be the device side that is the cause of this bug?

[sirhcel]

Hello @alecct-exi,

it sounds a bit strange to me that that no data will be received at all - but I'm sure we'll get to the bottom of this and I've got a bunch of questions for you:

1. Which operating system and which serial hardware are you using on the host side?
2. The case of transmitting 63 byte long "packets" works well and as expected?
3. Which communication settings are you using on the host?
4. What hardware are you using on the embedded side?
5. Is your serial communication happening over RX and TX UART lines or does the embedded device provide some sort of USB serial interface?
6. Do you have by chance an oscilloscope at hand to double check that there is any data transmitted at all from the embedded device?
7. Is there by chance a FIFO buffer on the embedded device which might get filled up with 64 bytes of data and require more care than the case of sending less data?
8. How is a "packed" from the embedded device defined?
9. Is the embedded device still alive and responsive after attempting to transmit 64 bytes (in the sense of not having panicked/restetted/...)