Yet another SERIN2 question

Howdy

I've fought this long enough - now am asking for help.

What I have is a serial LCD backpack with a keypad interface as well. Using a PIC 16F870 . That all works fine.
Sending serial characters, custom characters, etc to the LCD works fine.

The problem I have is getting data back from the keypad.

How it works is a request is sent to the keypad using a SEROUT2 command, ($FE,$1B,) an interrupt is returned, (active low), and after it goes high the key number is returned serially. This all works, I have attached a screen shot of the data transmissions from my logic analyzer.

What I can't get to work is the SERIN2 to actually get the key value back in.
As I said, the serial data (byte) is coming back, but the SERIN2 just "hangs", and never brings the data in.(must not see it) I tried using a timeout and label in the SERIN2 statement, but that was counter productive, 'cause the data was not being seen anyway.

here is a short code segment

serout2 Tx,84, [$FE,$1B] ' request for key data (code for this backpack)
pauseus 500
serin2 Rx,84,[key] ' get the key pressed from keypad buffer
pauseus 500
serout2 Tx, 84, [$FE,$0C,1,0,#key] 'display it on LCD line 2, position 1

key jas been defined as a byte variable

Tx is PORTC.7 and Rx is PORTC.6

The interrupt is returned to PORTC.5

4 Mhz oscillator is defined

The attached screen shot from my logic analyzer shows the interrupt line, data request, and serial data returned. A decimal "9" is what is returned in this case.

I've tried several variations of the SERIN2 command ( even tried SERIN with the "modedefs.bas" included )

Should I be trying to receive the data in an interrupt routine? That does not seem necessary - - -

Something simple, I'm sure - but I am stumped.

Thanks

Ken

can't seem to get this to work . .

Sorry - I did not attach this correctly

Ken

Hi Ken,
We just saw something like this a month or so ago, and what I learned from that thread is serin2 must have a non numeric character follow the numeric data in order to continue on it's way.<br>
EDIT: AHAA I found it :http://www.picbasic.co.uk/forum/showthread.php?t=10786

Hi all

It must have been timing related. I revised the code to :


serout2 Tx,84, [$FE,$1B] 'Request data from Keypad

pauseus 100 ' added a short delay

serin2 Rx,84,10,cont,[key] ' put a Timeout & jump in so the SERIN2 will wait
' for a while for the data to come back

cont: ' label to "jump to" if no data

pause 50 'Not sure if this is needed, will play with it some

serout2 Tx, 84, [$FE,$0C,1,0,#key] 'the decimal key value is now displayed
' The keypad defaults to 0 if a request
'is made and no key pressed

Anyway, now it works great. Learned something in the process too !

You have 4 open threads for the same problem ! WHY ? Please continue the saga within the original post, otherwise how do we know where to post our ideas as to how to help you.

Greetings
How about some code...
I'm use a system using 9 pics all using serin2/out2

Note after initiating the read pause for 10ms for the write.
This cured the universe for us.
other option is to use a single clock source.