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635 buffered commands

ElmerFudd

New member
So I'm trying to send multiple commands (back to back) to the 635 (USB) and it only seems to recognize the first one (command format and crc's look good - to me at least) - Total data length is 52 bytes (I'm setting up special chars for large numbers).. Single Command packet is below (containing mulitple commands).

9 9 0 7F 7F 60 60 60 60 3C 1E C4 CE 9 9 1 3 3 3 63 63 3E 1C 0 D 6A 9 9 2 C 1C 1C C C C C C 5 52 9 9 3 C C C C C 1E 1E 0 E1 B4

I guess my question is, will the 635 buffer up the commands?, and process in the order they are received? Or discard them if it's greater than a certain length..or am I just not seeing the error of my ways :)

Thanks much,

ef.
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USB LCD Displays - Graphic and Character LCDs with a Keypad

CF Tech

Administrator
You should wait for the acknowledge packet from the CFA-635 before sending the next packet.

You can use a delay to five the module time to process the packet, but that is problematic if the processing time for a packet is ever changed.
 

ElmerFudd

New member
I was waiting for that... Don't suppose you know how many bytes it can buffer? If I send only three messages (total of 39 bytes) Seems to work ok.. Two at a time is good too (26 bytes)...

My little micro is so impatient....

Oh well, don't hurt to ask..

Thanks,
ef.
 

CF Tech

Administrator
You want fast or reliable? Reliable == wait for the acknowledge. :)

Two at a time is good too (26 bytes)...
Officially just one outstanding packet is allowed, without respect to length. To buffer the longest packet of 22 data bytes, the buffer must be 27 at least bytes long ;)

three messages (total of 39 bytes) Seems to work
Which could be understood since the CFA-635 is busy pulling packets out as fast as it can.
 
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