I2C Device discovery - GCB code to discover devices.

[Anobium]

Sample code to discovery I2c devices. This requires the i2C libaries dated after Jan 2014.

[Anobium]

The code

~~~~~
' change the processor
#chip 16F1937, 4
#config Osc = intOSC, MCLRE_OFF, PLLEN_ON, VCAPEN_OFF

' Define I2C settings - CHANGE PORTS
#define I2C_MODE Master
#define I2C_DATA portc.4
#define I2C_CLOCK portc.3

' Define an LED port - this is not working at the moment... I want to flash the LED to count out the Device ID
' CHANGE PORTS
#define D1 LATD1
Dir PORTD.1 Out

' CHANGE PORTS AND/OR CHANGE TO SOFTWARE RS232
' Define the USART port
#define USART_BAUD_RATE 9600
#define USART_BLOCKING
#define SerInPort PORTc.7
#define SerOutPort PORTc.6
'Set pin directions
Dir SerOutPort Out
Dir SerInPort In

initserial:
wait 15 ms
HSerSend 27
HSerPrint "[2J"
HSerSend 27
HSerPrint "[0"
HSerSend 59
HSerPrint "0H"
HSerPrint "Great Cow Basic - Discovery I2C Device": crlf ( 1 )
HSerPrint "Searching I2C address space": crlf (2)

  for deviceID = 0 to 255
    I2CStart
    I2CSend deviceID

    if I2CDetectSend then
      HSerPrint "ID : "
      HSerPrint deviceID
      HSerPrint " (0x"
      HSerPrint hex(deviceID)
      HSerPrint ") - "
      HSerPrint "I2C Write": crlf ( 2 )
      FlashLED 1, @PORTD, 1
    end if

    I2CStart
    I2CSend deviceID
    I2CReceive device_result

    if device_result <> 255 then
      HSerPrint "ID : "
      HSerPrint deviceID
      HSerPrint " (0x"
      HSerPrint hex(deviceID)
      HSerPrint ") - "
      HSerPrint "I2C Receive": crlf ( 2 )
      FlashLED 1, @PORTD, 1
    end if

  next
  HSerPrint "End of Device Search": crlf ( 2 )
  I2CStop

END

Function I2CDetectSend ()
dim I2CByte as byte
I2CByte = 0: 'this is test byte to send
dim I2CGetAck
I2CGetAck = true
Dim function_result
function_result = false

#if I2C_MODE = Master
  I2C_CLOCK_LOW
  Wait I2C_END_DELAY

  'Send highest bit first
  For I2CCurrByte = 1 to 8
    If I2CByte.7 = On Then
      I2C_DATA_HIGH
    Else
      I2C_DATA_LOW
    End If
    Rotate I2CByte Left

    Wait I2C_END_DELAY
    I2C_CLOCK_HIGH
    Wait While I2C_CLOCK = Off
    Wait I2C_CLOCK_DELAY
    I2C_CLOCK_LOW
    Wait I2C_END_DELAY
  Next

  If I2CGetAck Then
    I2C_DATA_HIGH
    Wait I2C_END_DELAY

    I2C_CLOCK_HIGH
    Wait While I2C_CLOCK = Off
    Wait I2C_CLOCK_DELAY
    For I2CCurrByte = 0 to 255
      If I2C_DATA = 0 Then
        I2CGetAck = False
        'If data line goes low, ack has been received
        function_result = true
        Goto I2CAckEndlocal
      End If
      Wait I2C_END_DELAY
    Next
    'No ack received
    I2CAckEndlocal:
    I2C_CLOCK_LOW
    Wait I2C_END_DELAY
    I2C_DATA_LOW
    Wait I2C_END_DELAY
  End If

  'Wait one bit length
  Wait I2C_BIT_DELAY
#endif
I2CDetectSend = function_result

end sub

' 1.01 added USART SUPPORT and PORT

function crlf (Optional num As byte = 1, Optional nport As byte = 1 )

#ifdef USART_BAUD_RATE
  for loopcrlf = 1 to num
    HSerSend 13
    HSerSend 10
  next
#endif

#ifndef USART_BAUD_RATE
  for loopcrlf = 1 to num
    SerSend nport,13
    SerSend nport,10
  next
#endif

end function

Sub FlashLED ( In loopcount, In Destvar as word, In Destbit)

 for loopx = 0 to 10
        Poke  Destvar, Peek(Destvar) or Destbit
        wait 30 ms
        Poke  Destvar, Peek(Destvar) AND NOT Destbit
        wait 30 ms
next
wait 1 s

End Sub