Propeller with Parallax GPS Receiver Module

Comments

• El Paisa Posts: 375

  2006-10-10 02:51 edited 2006-10-10 02:51

  Hi,
  
  This may help you.
  
  · serial.str(@msg1)·····
  · serial.tx($00)
  · waitcnt(900_000+cnt)
  
  DAT
  · msg1··· byte··· "!GPS",0
  
  I use this format to communicate with a uMMC card writer/reader.
  
  Hope this help.
• El Paisa Posts: 375

  2006-10-10 02:57 edited 2006-10-10 02:57

  Hi again,
  
  The program I use to communicate with a uMMC card writer/reader is :
  
  ''*****************************
  '' uMMC_1.spin
  ''*****************************
  
  CON
  
  · _clkmode····· = xtal1 + pll16x
  · _xinfreq····· = 5_000_000
  · RX_PIN······· = 2
  · TX_PIN······· = 3
  · MODE········· = %0000································ ' see FullDuplexSerial.spin for description
  · BAUD········· = 9600
  ·····
  VAR
  
  ······· long··· k
  
  OBJ
  
  ······· term··· : "tv_terminal"
  ······· serial· : "fullduplexserial"
  
  PUB start | i
  
  · serial.start(RX_PIN, TX_PIN, MODE, BAUD)·········· ' initialize serial object
  · waitcnt(4_000_000+cnt)
  
  
  ··· term.start(12)
  ··· term.str(@title)·
  ··· waitcnt(40_000_000+cnt)
  
  '

  ---

  [noparse][[/noparse]Main starts here]

  ---

  
  · term.str(@msg1)
  · term.out($09)····
  · serial.str(@msg1)·····
  · serial.tx(13)
  · waitcnt(900_000+cnt)
  · repeat until k==">"·········
  ··· k:=serial.rx
  ··· term.out(k)
  
  
  
  DAT
  · title·· byte··· "First uMMC Read/Write",13,13,0
  · msg1··· byte··· "V",0
• Michael Rankin Posts: 2

  2006-10-10 02:57 edited 2006-10-10 02:57

  I modified my code to implement your change and I get the same output:
  
  0x21 which is !
  0x47 which is G
  It looks like I am just getting back the command I am sending. I don't know if the GPS module is returning that or the code is reading it from memory
  
  Post Edited (Michael Rankin) : 10/10/2006 1:47:18 PM GMT
• ALIBE Posts: 299

  2006-10-10 18:37 edited 2006-10-10 18:37

  Michael,
  try this following code. Note, I have removed the use of fullduplex and am using 2 code snippets courtesy of Mike Green. It works like a charm for me in my AC4790 work I am doing w my ALIBE project.
  hope this works for you
  

  Const
    #1, Pin_GPS
  Var 
    byte buffer[noparse][[/noparse]256] 
  
  Pub Main |s  
    DirA[noparse][[/noparse]Pin_GPS]~~ 
    repeat 
      buffer[noparse][[/noparse]0] := "!"
      buffer[noparse][[/noparse]1] := "G"    
      buffer[noparse][[/noparse]2] := "P"    
      buffer[noparse][[/noparse]3] := "S"
      buffer[noparse][[/noparse]4] := $0
      txData 
      rxData 
      
  PUB rxData | c, x 
    x := 0 
    repeat until (c := SerialIn(Pin_GPS, 4800,1,8) ) == 0 
      buffer[noparse][[/noparse]x++] := c 
    buffer[noparse][[/noparse]x] := 0 
  
  PUB txData|x 
    x := 0 
    repeat until (buffer[noparse][[/noparse]x] == 0) 
     SerialOut(Pin_GPS, buffer[noparse][[/noparse]x++], 4800, 1, 8) 
  
   
  '//
  '// Code courtesy of Mike Green
  '//
  PUB serialIn(pin, Baud, mode, bits) | bitTime, time 
    {{ Accepts asynchronous byte value on defined pin, at Baud, in mode for #bits 
       Mode: 0 = Inverted - Normally low Constant: Inv 
       1 = Non-Inverted - Normally high Constant: NInv }} 
     
     dira[noparse][[/noparse]pin]~ ' Set up input pin as an input 
     bitTime := clkfreq / Baud ' Calculate bit time for Baud 
     waitpeq(mode << pin, |< pin, 0) ' Wait for idle (should be idle) 
     waitpne(mode << pin, |< pin, 0) ' Now wait for start of start bit 
     time := cnt ' Wait until middle of start bit 
     waitcnt(time += bitTime >> 1) 
     repeat bits ' Sample input at the middle of 
       waitcnt(time += bitTime) ' each data bit time for #bits 
       result := ((ina[noparse][[/noparse]pin] ^ (1 - mode)) << bits | result) >> 1 
  
  
  '//
  '// Code courtesy of Mike Green
  '//
  PUB serialOut(pin, char, Baud, mode, bits ) | bitTime, time 
    {{ Send asynchronous character (byte) on defined pin, at Baud, in Mode for #bits 
       Mode: 0 = Inverted - Normally low Constant: Inv 
       1 = Non-Inverted - Normally high Constant: NInv }} 
    outa[noparse][[/noparse]pin] := mode ' Set up output pin with the proper 
    dira[noparse][[/noparse]pin]~~ ' idle state and as an output 
    bitTime := clkfreq / Baud ' Calculate bit time for Baud 
    char := ((1 << bits | char) << 1) ^ (mode == 0) ' Add start/stop bits & invert if needed 
    time := cnt 
    repeat bits + 2 ' Send each bit based on baud rate 
     outa[noparse][[/noparse]Pin] := char 
     char >>= 1 
     waitcnt(time += bitTime) 
    waitcnt(time += bitTime * (bits + 2)) ' Allow a character time for pacing 
  
  

  
  

  
  
  
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