RS-232 performance

[awneil]

@jonpio

Is this normal ?

Yes:

Q2686 UART receive buffer size is limit only 56?

Obviously (well, it should be obvious), the first thing you need to determine is whether the external device is actually transmitting the junk, or if there’s a bug in your software that’s causing the junk to appear. How, exactly, did you obtain those traces? Is the “junk” always at the end of the “good” data like that? It’s not a limitation of the Q26 buffer - it’s just how FCM works. Maybe there’s a bug in your software implementation? Maybe there’s a bug or fault in your hardware - eg,…

FCM and WIP

No, that is not a valid assumption at all. FCM does not know what constitutes a “message” according to your rules - so it cannot tell where you think the message should end. It therefore gathers bytes according to its own rules - which are the only ones it can know - and it tells you how many bytes it has collected. It is up to you to interpret those “chunks” according to your own message rules. No - not necessarily. The FCM data handler tells you precisely how many characters it is passi…

Q2686 UART Buffer size

Where, exactly, in the ADL USer Guide did you read that? I think you are confusing the UART (hardware) with the Flow Control Manager (FCM) - an ADL service? This has nothing to do with the UART hardware - it is in the nature of how FCM gathers received bytes to be delivered to the Data Handler. It would be very inefficient if FCM were to make a Data Handler call on every single received byte…! No, you do not need to - and you can’t, anyhow! You must write your code to receive the data in …

FCM Newby

In fact, it is very much like dealing with a UART with a built-in FIFO - you get an Event when the FIFO is “full”, or when some bytes have been received and it’s not full, but there’s been a sufficient delay with no further characters received.

What's a "block"?

Hi awneil, Sorry for the delayed reply. The block that is received by FCM is nothing but the data that is received over the FCM flow. For instance, if you have subscribed to FCM flow for V24 and have switched the flow to data mode, then whatever your external application (eg. hyperterminal) sends to the module in one go constitutes one block. When the external application sends something to the module, that is received in the UART FIFO buffers. This leads to the generation of an interrupt. No…