FullDuplexSerial Receive only

Capn_Dave

Is there a way to initialize the FullDuplexSerial object to not consume a transmit pin.
I am using the RF ID TAG READER and do not need a·transmit pin.


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Caught in the PropWash

Timmoore

Set the pin to -1

Ariba

Here is an Serial-Receiver only object. It has lower byte count, supports higher baudrates, and can also receive 9 databits (i.e for a parity bit).

Andy

Capn_Dave

I tried using -1. It becomes pin 31, killing recevie on the pin 31.

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Caught in the PropWash

Capn_Dave

Ariba,
Thanks. I thought of doing that but wanted to have just one serial object in my library.
Thanks again

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Caught in the PropWash

Timmoore

try pcfullduplexserial4fc from object exchange that definitely supports -1 since I did it.
http://obex.parallax.com/objects/340/

Capn_Dave

Thanks, I'll give that a try.

I think the -1 becomes a 31 in the ··· ·shl···· txmask,t2··· instruction.



I verified this must be happening with the following code transmitting on pin 30

com.start(31,-2,0,9600)

com.str(string("TRANSMITTING USING PIN -2"))··






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Caught in the PropWash

Capn_Dave

I found the easiest way to get around my problem.

I used mode = 4 for open drain on TX
I still used -1 as the TX for readability

OBJ
· com:"fullduplexserial"
· reader:"fullduplexserial"

PUB START
··com.start(31,30,0,9600)···· ' start com port
· reader.start(0,-1,4,9600)··· ' start reader port

TNANX


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Caught in the PropWash

Timmoore

There is explicit code in the 4 port version that checks for -1. The tradeoffs are its bigger in code but supports up to 4 ports with 1 cog. Does check for -1, optionally supports cts/rts flow control. You can access the ports from multiple objects at the same time thouh you have to handle any interleaving rx/tx issues. If you want > 4 ports you have to do some work (copy and modify 1 variable) but it increases code size.

Chris Savage

Why not use the same pin number for send and receive and use open baud mode?

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Chris Savage
Parallax Tech Support