Can someone help me? Serial Communications

Furball · 2009-08-19 16:11

Im kind of new to the .spin language and im in need of some help, i have been doing a little homework on the propeller chip but now im in need of some help, im needing a program that when a switch is closed it will output via RS232, a hex statemet of FE 1E, for some reason i think im making this harder than it needs to be. Can someone help me learn what im going wrong?

billiam2536 · 2009-08-19 16:19

To know what your doing wrong, people have to know what your doing Period. I suggest you upload your current code.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Working on getting money for autopilot project. Come check out my site if your interested in the project. Maybe go to the bottom of the page

Carnibus · 2009-08-19 16:33

I've never used it but the fullduplexserial object has a trasmit hex method you could probably use.

JonnyMac · 2009-08-19 17:02

Maybe... depends on the device. I'm guessing it's a Scott Edwards display as they use a $FE header followed by the instruction byte. If one had a serial object called display then the .tx method is all that's required:

display.tx($FE)
display.tx($1E)

Furball · 2009-08-19 17:12

Actually its a R4x/R8x Pro
RS-232 E3C Networkable Relay Controllers that needs FE 1E to turn on all the relays, its 9600 baud

blackmesa82 · 2009-08-19 18:37

The following routine works well up to at least 38,400 baud.

You could send fe 1e with


CommTX(@relay)

Simply add the constants to your CON section, setting TX to your transmit pin. Messages are defined in the DAT section and must be terminated with 0.

Here is the code:


con

BAUD = 9600
TX = 6                          ' RS-232 transmit pin

dat

sorry   byte  "I'm sorry, Dave. I'm afraid I can't do that.",13,10,0
relay   byte  $fe,$1e,0




pub CommTX(message) | data,mark,clks,i

clks := clkfreq / BAUD
i~

repeat while byte[noparse][[/noparse]message][i]
  data := byte[noparse][[/noparse]message][i]
          
  data := data <<1
  data := data | %1_00000000_0                          ' add start and stop bits
  mark := cnt + clks

  repeat 10
    outa[noparse][[/noparse]TX] := data & %0000000001                     ' send data packet
    data := data >>1
    waitcnt(mark)
    mark += clks

  i++

[/i][/i]

(edit: sorry, I missed the @ in the CommTX call.)

- eeo

Post Edited (blackmesa82) : 8/19/2009 6:55:04 PM GMT

StefanL38 · 2009-08-19 18:37

Hello Furbal,

as you seem to ´be a newbee I would like to state some additional things

the FullDUplexSerial-objects sends data at the specified baudrate in 8N1-format which is very common
8N1 8 databits no parity 1 stopbit
but there are also others like 7E2 7 databits equal parity 2 stopbits or 8N2, 8E1, or 8O1, etc. etc.

the parameter mode specifies details about the electronical circuit of the Rx and the Tx-line
mode 0 is common

I guess the Relay-control expects real RS232 voltage-levels which is +12V/-12V.
The propeller-IO-pins deliver 0V/3.3V so you need a voltage-levelshifter chip like the MAX2323

you should use a current-limiting resistor of 150 Ohms to avoid damaging an IO-pin if the IO-PIN is accidently configured wrong
the IO-PIN connected to the switch

you should use a PULL-down-resistor of 10kOhm to get a clear defined state of the IO-PIN while the switch is open
the Pull-down-resistor as its name says pulls down the IO-PIN to low=0V.
Without a Pull-down-resistor the state of the IO-PIN is free floating and the state will change between low and high
in an unpredictable way

below is a demoprogram that shows one of 2 dozens of solutions to what you have described above
download the program to the EEPROM
then start the PST.EXE (Parallax Serial Terminal) adjust baudrate to 115200
reset the prop while PST is connected to the prop and watch the debug-output

depending on what you want to do in the end another solution might be more suitable

CON
  _clkmode = xtal1 + pll16x
  _xinfreq = 5_000_000

  c_RxPin = 20 'you have to adjust this number to YOUR IO-PIN-number
  c_TxPin = 21 'you have to adjust this number to YOUR IO-PIN-number
  c_mode  = 0
  c_baud  = 9600

  'you have to adjust this number to YOUR IO-PIN-number
  'where the button is connected to
  c_IO_Pin_Button = 0 

OBJ
  debug          : "FullDuplexSerial" 'use programming connection for debugging
  RS232RelayCont : "FullDuplexSerial" 'serial connection to RS232Relay-control

    
PUB Demo_Send_Char_on_buttonpress

  debug.start(31,30,0,115200)
  RS232RelayCont.Start(c_RxPin, c_TxPin,c_mode, c_baud)
  debug.str(string("Serial-driver cogs started ",13,13))

  DIRA[noparse][[/noparse] c_IO_Pin_Button] := 0 'define IO-PIN as input
  
  debug.str(string("wait for IO-PIN No "))
  debug.dec(c_IO_Pin_Button)
  debug.str(string(" to be high = 3.3V",13))

  'stay inside this repeatloop until IO-Pin is high
  'works if IO-PIN has a Pull-down-resistor
  repeat until INA[noparse][[/noparse] c_IO_Pin_Button] == 1 

  debug.str(string("IO-PIN No "))
  debug.dec(c_IO_Pin_Button)
  debug.str(string(" detected as high = 3.3V",13,13))

  debug.str(string("wait for IO-PIN No "))
  debug.dec(c_IO_Pin_Button)
  debug.str(string(" to be low = 0V",13))

  'stay inside this repeatloop until IO-Pin is low
  'works if IO-PIN has a Pull-UP-resistor
  repeat until INA[noparse][[/noparse] c_IO_Pin_Button] == 0 

  debug.str(string("IO-PIN No "))
  debug.dec(c_IO_Pin_Button)
  debug.str(string(" detected as low = 0V",13,13))

  RS232RelayCont.tx($FE)
  RS232RelayCont.tx($1E)

  debug.str(string("$FE $1E was send to IO-PIN No "))
  debug.dec(c_TxPin)
  debug.str(string(13,"at "))
  debug.dec(c_baud)
  debug.str(string(" baud  (8N1 = 8 databits no parity 1 stopbit)",13))

  debug.str(string("program is running commmand beyond this line of code",13))

  repeat

best regards

Stefan

Cluso99 · 2009-08-19 22:37

Welcome to the forum. As you have seen, if you have any questions just ask and enjoy the prop·

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Links to other interesting threads:

· Home of the MultiBladeProps: TriBladeProp, RamBlade, TwinBlade,·SixBlade, website
· Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
· Prop Tools under Development or Completed (Index)
· Emulators: Micros eg Altair, and Terminals eg VT100 (Index) ZiCog (Z80) , MoCog (6809)
· Search the Propeller forums·(uses advanced Google search)
My cruising website is: ·www.bluemagic.biz·· MultiBladeProp is: www.bluemagic.biz/cluso.htm

Can someone help me? Serial Communications

Comments