Wait for a string on a serial port

[RuudNL]

I just tested it, and it works.
At first I got the impression that is was unreliable (to the same degree as what I had created), but after some experimentation it showed that I needed a pull-up resistor at the output of the MIDI port. (In fact you should use an optocoupler for this.)
But with a pull-up resistor it works now without any problems. So I think my code would work also, but this code is more compact, so I will keep using it.
Many thanks again!

[Scampy]

This is the code I use for my serial comms

RCIF                VAR PIR1.5                    ' USART receive flag
Char                VAR BYTE                      ' USART byte received
GIE                 VAR INTCON.7 
nTest               var byte

and then in the main loop of the code

FOR TempWD = 0 TO 500
    IF RCIF=1 THEN GOSUB coms                   ; Check to see if PC application connected
    PAUSE 1
next TempWD

And then the Comms subroutine

HSERIN [nTest]
    SELECT CASE nTest
    CASE "Q"                    ; if Q then send data to PC
    Goto Term_TX 
    CASE "S"                    ; if S then receive data from PC
    goto Term_RX
return

The Term_RX / Term_TX subroutines are then used with HSERIN or HSEROUT to receive and send data. As can be seen from the code I use Q and S as the keys to communicate with a PC application which receives variable data and populates text boxes, or if the value are changes in those text boxes and the update button clicked, the PS sends the new values for the variables..

Hope that helps

[Art]

With just a 3 byte buffer the whole thing could be non blocking,
and the 1 timeout might even be able to be changed to zero for no delay at all.

buffer var byte[3]
inputbyte var byte

main:
'
HSERIN 1,nodat,[inputbyte]	‘ receive next byte
buffer[2] = buffer[1]		‘ rotate into buffer
buffer[1] = buffer[0]
buffer[0] = inputbute
if (buffer[2] = 176 && buffer[1] = 44) then
if buffer[0] = 69 then portb.0 = 1
if buffer[0] = 5 then portb.0 = 0
endif
nodat:				' timeout label for no byte received
'
// the rest of the program
‘
goto main

[flotulopex]

Hi,

I'm trying to do almost the same as RuudNL but I'm having some trouble to make it work.

From the Serial Communicator (MECANIQUE), using a FTDI TTL232R serial cable, I send a command identifier and a value to the PIC.

' ====== FUSES ====================================================================================
' PIC 12F683
@ __CONFIG _FCMEN_OFF &_IESO_OFF &_BOD_OFF &_CPD_OFF &_CP_OFF &_MCLRE_OFF &_PWRTE_OFF &_WDT_OFF &_HS_OSC

' ====== REGISTERS ================================================================================
' Registers   76543210
ANSEL      = %00000000  'Disable analog inputs
ADCON0     = %00000000  'ADC is OFF
CMCON0     = %00000111  'Comparator is OFF
OPTION_REG = %10000000  'Pull-Ups disabled
TRISIO     = %00000001  'Inputs/Outputs
GPIO       = %00000000  'High/Low

' ====== DEFINES ==================================================================================
DEFINE OSC 8

' ====== VARIABLES ================================================================================
TX_ON  var GPIO.2 'LED
DataIn var GPIO.0
Switch var byte
BdRate var WORD
          
' ====== INITIALIZE ===============================================================================
TX_ON  = 0
Switch = 0
BdRate = 49236 '9600 OIN

' ====== PROGRAM ==================================================================================
MAIN:
    SERIN2 DataIn,BdRate,[WAIT("Identifier"),Switch]
    IF Switch = 1 THEN TX_ON = 1
    IF Switch = 0 THEN TX_ON = 0
    GOTO MAIN
END

Unfortunately, the PIC doesn't react to the incoming data.

I might not use the correct syntax in the Serial Communicator.

Do I have to type something different as this here:


Thanks for any help.

[Scampy]

Roger, what have you configured the serial port to. Reading the manual the value for MODE if using 9600 baud rate, with the normal 8 bit, no parity, 1 stop bit the value is 84, but you have bdrate (same as mode in the manual) set to 49236....

from the manual - SERIN2

Some examples of Mode are: Mode = 84 (9600 baud, no parity, true)

[flotulopex]

Scampy,

I have connected the FTDI cable directly to the PIC this is why I use this particular mode

To make sure the serial communication really "happens", for testing purpose, I have configured the PIC to send data to the Serial Communicator software.

So I think I may have a syntax issue here.

[richard]

MAIN:
SERIN2 DataIn,BdRate,[WAIT("Identifier"),Switch]
IF Switch = $31 THEN TX_ON = 1
IF Switch = $30 THEN TX_ON = 0
GOTO MAIN
END

or

in serialtool send

Identifier#1