Need help creating a PIC simulation hardware controller(USO)

I am trying to create my own controller, which will receive data from USO and then use them to output values to gauges, fans, and relays etc.

I am basically using a PIC16F887 microcontroller programmed trough MikroBasic and a MAX232 signal adapter IC to connect to my PCs serial port..

I have been able to read and output a single value from USO and X-SIM, but I am having problems writing the code to read 2 or more values. Could you please explain me how should it be done? What would be the general idea?

My current approach is to output from USO a string like this:
A~a01~B~a02~

A: indicates that the following value will be for CHANNEL A
~a01~: value for CHANNEL A
B: indicates that the following value will be for CHANNEL B
~a02~: value for CHANNEL B

and the PIC would run this code:

Code:

while (TRUE)                         'Endless loop
  if (UART1_Data_Ready() <> 0) then      ' If data is received,
    UART_RX = UART1_Read()               ' read the received data,
  end if

select case UART_RX                         'Examine what is the data that was received
  case A                                  'If it is A, then the next value is for A channel
    if (UART1_Data_Ready() <> 0) then      ' If data is received,
    VALUE.A = UART1_Read()                   ' read the received data for CHANNEL A
  end if

  case B                                 ' If it is B, then the next value is for B channel
    if (UART1_Data_Ready() <> 0) then      ' If data is received,
   VALUE.B= UART1_Read()                   ' read the received data for CHANNEL B
  end if
 
  case else                                ' IF it is nothing from the above, then start re-reading
    goto start
end select

But it does not work. It instantly makes VALUE.A = 255 and VALUE.B =255 and nothing else..
Any help would be greatly appreciated!
Thank you!

I think this is a wrong forum to ask. I would try a PIC related site where people have more knowledge of your chip and the compiler your using.

I am working on a controller as well and I would be happy to help, but I program AVR's in AVRStudio4.
My packets have 2 start bytes: ST~a01~~a02~... and so on. After I receive the two start bytes, I begin to fill up an array with the axis data. It works for any number of axis, I just have to make the array large enough. Then I can put the bytes together for a 16bit value or do any scaling, calculations an whatnot.

Your method I like better and I will probably do something similar. It is more flexible because you can identify and do specific things to each axis data. Using 8-16-32 bit resolution and mixing them is a lot easier for this reason too. The only thing I would be concerned about is the fact that a character is just an other 8bit number as well. If your axis data matches your character code, things can get messy and data can be mixed up.

Guys, thank you for your answers! I am on holiday now, away from my internet connection and i have to sniff around to find a hotspot to check the forum.

I have finally nailed it! I made it possible to read as much as 255 values from serial USO, using any PIC microcontroller.


I am using a PIC16F887 to read values from USO, and then use them to 2 PWM outputs (could be used as motor-driver, or as dimable LED driver). In this example, i use 2 LEDs to output 2 values, for LEFT engine RPM (LEFT LED) and RIGHT engine RPM (RIGHT LED).

X-sim sends (through USO) a string of BYTES (8-bits) of game values followed by a stop character (S) . The PIC receives the bytes coming from USO and stores them consequentially into the OUTPUT variable. The reading stops when the stop character S is received AT A CERTAIN PREDEFINED POSITION. After saving this string to OUTPUT, you are able to choose which value you want to use. The values are saved in the order they are sent through USO.

If for example you have:
~a01~ = 11111111
~a02~ = 00000000
S = 01010011

and you have set USO to send this : ~a01~~a02~S

then the OUTPUT would be: 111111110000000001010011

and you can use:
OUTPUT[0] = 11111111 (which is ~a01~)
OUTPUT[1] = 00000000 (which is ~a02~)
OUTPUT[2] = 01010011 (= S) in whatever way you find it necessary.

My testboard consists of a PIC16F887, a MAX233 IC (adapter between PIC and PC), and 2 LEDs with 470Ohms resistors, just to output the % of each value. 0% is fully off LED, and 100% is fully enlightened LED. Total cost of around 14Euros here in Greece.


The general idea of it, is described by this code written in MikroBasic PRO:

Code:

program PicUSO
' * DESCRIPTION
' PWM Fan controller through PIC16F887. RS232 (serial port) communication.
' To be used with X-SIM software, USO output. NuMcA 12-2009.
'
' * TEST CONFIGURATION
'     MCU:            P16F887
'     Dev.Board:      breadboard 
'     Oscillator:     internal 8Mhz

dim dutyR, dutyL as byte	' Values for Left LED and Right LED
dim output as string[3]		' Output variable holds the USO values. 
				' [output] = [VALUE.A] +[VALUE.B] +... +[S to stop]  

sub procedure InitMain()	' Configure PIC16F887 options
  OSCCON = %1111101	     ' Internal oscillator set to 8MHz
  ANSEL = %00000001          ' Configure AN0 pin as analog
  TRISA = %00000001          ' PORTA is input

  TRISC = %00000000          ' PORTC is output for pulses
  PORTC = %00000000

  TRISD = %00000000          ' PORTD is output (not used)
  PORTD = %00000000          ' initialize PORTD
end sub

sub procedure InitLED()      ' blink twice the indicator LEDs on startup
  PORTC.1 = %1
  PORTC.2 = %1
  delay_ms(100)
  PORTC.1 = %0
  PORTC.2 = %0
  delay_ms(400)
  PORTC.1 = %1
  PORTC.2 = %1
  delay_ms(100)
  PORTC.1 = %0
  PORTC.2 = %0
  delay_ms(400)
end sub

main:
InitMain()              'Initialize MCU registers

InitLED()               'Blink LEDs twice on start-up

UART1_Init(9600)        ' Initialize UART module at 9600 bps
Delay_ms(100)           ' Wait for UART module to stabilize

PWM1_Init(25000)         ' Initialize PWM1 module at 25KHz
PWM2_Init(25000)         ' Initialize PWM2 module at 25KHz

PWM1_Start()             ' start PWM1
PWM1_Set_Duty(0)         ' Set current duty for RIGHT LED to 0

PWM2_Start()             ' start PWM2
PWM2_Set_Duty(0)         ' Set current duty for LEFT LED to 0

while (TRUE)                         'Endless loop
  if (UART1_Data_Ready() <> 0) then  ' If data is received,
    UART1_Read_text(output,S,3)    ' read the received data and save it to OUTPUT, until 					     ' the 3rd character is S.
  end if
  dutyL = output[0]                  ' Data for LEFT channel is 1rst byte
  PWM2_Set_Duty(dutyL)             ' Set current duty for LEFT LED
  dutyR = output[1]                  ' Data for RIGHT channel is 2nd byte
  PWM1_Set_Duty(dutyR)             ' Set current duty for RIGHT LED
wend
  PWM1_stop                          ' Stop RIGHT PWM
  PWM2_stop                          ' Stop LEFT PWM
end.

BOTTOMLINE:
if (UART1_Data_Ready() <> 0) then____' If data is received,
UART1_Read_text(output,S,3) _______' read the received data and save it to OUTPUT character string,
end if _____________________________' until the 3rd character is S.


I have trouble finding internet connection here, so i will post a MUCH more detailed description of the project, along with schematics and compiled code when i get back, or find a steady internet connection.. Hope you find it helpful, THANK YOU FOR YOUR ANSWERS!

Γεια σου NuMcA_[.gr]

Το ξερω οτι δειχνει δυσκολο, και μακαρι να μπορουσα να βοηθησω με τους PIC αλλα παντα προτιμουσα τους AVR... Αν εισαι Αθηνα παντως ευχαριστως να βρισκομασταν για καφε να το συζητουσαμε και να σου εξηγουσα πως λειτουργει ωστε να προσαρμοσεις τον κωδικα στο δικο σου.

Θανος

Thank you Tronic, for your kind words, we will speak through PM!
Happy New Year to all!