RS232 for two peripherals

[Mark Haines]

A friend and I are trying to use a 16F877 to manage a vehicle locator, and as such it needs to talk to both a GPS unit (Trimble Lassen SKII) and a radio modem.

We've got the modem working fine using #use rs232... it happens to be on the hardware UART pins, but we're using the software UART, obviously.

The problem occurs when we try to poll the GPS on two other pins. We get bytes on the serial line, but they're invalid. When attached to its test board and a PC, the GPS sends out valid information, but something appears to be corrupting the serial link with the PIC.

Any tips?
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This message was ported from CCS's old forum
Original Post ID: 1269

[Delene Mulley]

Don't know if it will help but I have managed to have 2 serial ports no problem. Both can send and receive. On the f877 I used pins c6 and c7 as my main port and pins e0 and e1 as my second port. I connected both ports onto a max232 and then outputed them

The thing to remember is that befor you use port 1, specify its #use and when you use port 2, specify its #use and you have do this everywhere through out your code.
An example of switching between 2 rs232 ports is given in the compiler hand book, under problems.

Delene

:=
:=A friend and I are trying to use a 16F877 to manage a vehicle locator, and as such it needs to talk to both a GPS unit (Trimble Lassen SKII) and a radio modem.
:=
:=We've got the modem working fine using #use rs232... it happens to be on the hardware UART pins, but we're using the software UART, obviously.
:=
:=The problem occurs when we try to poll the GPS on two other pins. We get bytes on the serial line, but they're invalid. When attached to its test board and a PC, the GPS sends out valid information, but something appears to be corrupting the serial link with the PIC.
:=
:=Any tips?
___________________________
This message was ported from CCS's old forum
Original Post ID: 1273