Is there any MCP23017 example code for keypads?

[David Briscoe]

Hi,
I'd like to use GCB to read from a 39 key keypad and write to upto 10 led's. This would use an MCP23017 port expander and a 4532 8 to 3 priority encoder (see attached example schematic-the MCP23017 replaces the SAA1061 chip). Is there any example code that uses a MCP23017 with a keypad and LED's? Thanks.

[Anobium]

Not a solution I have come across over the years I have been here. :-)

[mmotte]

There is a library file for MCP23017. That would be a good starting spot.

[David Briscoe]

Thanks. I'm a beginner with GCB. Where can I find (which directory?) this library file and how do I include it in a listing? I can probably start with turning an LED on and OFF. Is there an example of this anywhere? I've seen a few posts in the forum about the MCP23017 but nothing that is a clear working example. I'm mostly going to writing/polling to port pins.

[Anobium]

I have working examples of the MPC23xxx functions. Let me dig them out and post here.

[Anobium]

These are two subroutines that are used to test I2C communications of Great Cow BASIC. So, this code segment is part of a much larger test program.

Search for //!Here In GCStudio the calls will show up in RED.

This code segment shows how to setup, write and read.

The library is will documented but have you used I2C before ? What chip are you using ?
Do you have communications with the MCP ?

Evan

  #include <MCP23008.h>    //!Here
  #include <MCP23017.h>    //!Here


dim ug_stateofmcp23008
sub Showmcp23008

      //!Here
      #DEFINE MCP23008_DEVICE_1 0X48

      ANSI (  2, 40)
      ' BOLD OFF

      HSerSend 27
      HSerPrint "[1m"
      HSerSend 27
      HSerPrint "[37m"

      HSerPrint "MCP 23008 Device  "
      ' BOLD OFF
      HSerSend 27
      HSerPrint "[0m"

      ANSI (  3, 40)

      //!Here
      ' Is device present?
      I2CStart
      I2CSend ( MCP23008_DEVICE_1 )
      i2cstop
      //!Here

      if I2CSendState = False  then
        HSerSend 27
        HSerPrint "[1"
        HSerSend 0x3b
        HSerPrint     "31m"
        HSerPrint "Device Missing"
        HSerSend 27
        HSerPrint "[1"
        HSerSend 0x3b
        HSerPrint "32m"
        exit sub
      end if


      HSerPrint "All Ports to Output"
      ANSI (  4, 40)
      HSerPrint "Device Ports = 0x"

      //!Here
      ' setup MCP23008
      mcp23008_sendbyte(MCP23008_DEVICE_1, MCP23008_IODIR  , 0x00)' turn all pins output

      if ug_stateofmcp23008 = 0 then
         portsetvalue0 = 0xAA
         HSerPrint hex(portsetvalue0)

          //!Here
          ' set ports status on MCP23008
          mcp23008_sendbyte(MCP23008_DEVICE_1, MCP23008_GPIO, portsetvalue0 )' turn all pins off
          ug_stateofmcp23008 = 1
        else
          portsetvalue1 = 0x55
          HSerPrint hex(portsetvalue1)

          //!Here  
          ' set ports status on MCP23008
          mcp23008_sendbyte(MCP23008_DEVICE_1, MCP23008_GPIO, portsetvalue1 )' turn all pins on to state
          ug_stateofmcp23008 = 0
        end if
        HSerPrint "  "



      ANSI (  5, 40)
      HSerPrint "Read Device  = "
      //!Here
      ' read ports status on MCP23008
      mcp23008_readbyte(MCP23008_DEVICE_1, MCP23008_GPIO, ug_data )' read state


      if ug_stateofmcp23008 = 1 then
         HSerSend 27
         if ug_data <>  portsetvalue0  then
             HSerPrint "[1"
             HSerSend 0x3b
             HSerPrint     "31m"

          else
             HSerPrint "[1"
             HSerSend 0x3b
             HSerPrint "32m"

          end if
      end if

      if ug_stateofmcp23008 = 0 then
         HSerSend 27
         if ug_data <> portsetvalue1  then
           HSerPrint "[1"
           HSerSend 0x3b
           HSerPrint "31m"
        else
           HSerPrint "[1"
           HSerSend 0x3b
           HSerPrint "32m"
        end if
      end if

      HSerPrint "0x"
      HSerPrint hex(ug_data)
      HSerPrint "    "
      HSerSend 27
      HSerPrint "[0m"

end sub

dim ug_stateofmcp23017
sub Showmcp23017

      //!Here   
      #DEFINE MCP23017_DEVICE_1 0X40

      ddelay = 1
      //!Here
      mcp23017_sendbyte(MCP23017_DEVICE_1, MCP23017_IODIRA  , 0x00)' turn all pins output
      mcp23017_sendbyte(MCP23017_DEVICE_1, MCP23017_GPIOA, 0x00 )

      mcp23017_status = 1


      ANSI (  7, 40 )
      ' BOLD OFF
      HSerSend 27
      HSerPrint "[1m"
      HSerSend 27
      HSerPrint "[37m"
      HSerPrint "MCP 23017 Device  "
      ' BOLD OFF

      HSerSend 27
      HSerPrint "[0m"

      ANSI (  8, 40 )
      ' Is device present?
      I2CStart
      I2CSend ( MCP23017_DEVICE_1 )
      I2CStop

      if I2CSendState = False  then
        HSerSend 27
        HSerPrint "[1"
        HSerSend 0x3b
        HSerPrint     "31m"
        HSerPrint "Device Missing"
        HSerSend 27
        HSerPrint "[1"
        HSerSend 0x3b
        HSerPrint "32m"
        exit sub
      end if


    Set C off
    repeat 7                      ' Repeat this loop 7 times
           Rotate mcp23017_status Left      ' Rotate the portD to the left, shifting Carry Bit (equals 0 to first port)
           //!Here 
           ' set ports status on MCP23008
           mcp23017_sendbyte(MCP23017_DEVICE_1, MCP23017_GPIOA, mcp23017_status )
           wait ddelay ms         ' wait
'           Axe033cmd ( 254, 192 )
'           Axe033String ( BYTETOBIN( mcp23017_status)  )
           set c off
    end Repeat                    ' Loop
    wait ddelay ms


    repeat 7                      ' Repeat this loop 7 times, 7 prevents a double flash of one of the LEDs
         Rotate mcp23017_status Right
         //!Here
        ' set ports status on MCP23008
        mcp23017_sendbyte(MCP23017_DEVICE_1, MCP23017_GPIOA, mcp23017_status )
'        Axe033cmd ( 254, 192 )
'        Axe033String ( BYTETOBIN( mcp23017_status)  )
        wait ddelay ms           ' wait
        set c off
    end Repeat                    ' loop

    set mcp23017_status = 1               ' reinitialise the port
    //!Here
    mcp23017_sendbyte(MCP23017_DEVICE_1, MCP23017_GPIOA, mcp23017_status )' turn all pins off

      ANSI (  8, 40 )
      HSerPrint "All Ports to Output"
      ANSI (  9, 40 )
      HSerPrint "Device Ports = 0x"

      ' setup MCP23017
      //!Here
      mcp23017_sendbyte(MCP23017_DEVICE_1, MCP23017_IODIRA  , 0x00)' turn all pins output

      if ug_stateofmcp23017 = 0 then
         portsetvalue0 = 0x00
         HSerPrint hex(portsetvalue0)

          ' set ports status on MCP23017
          //!Here
          mcp23017_sendbyte(MCP23017_DEVICE_1, MCP23017_GPIOA, portsetvalue0 )' turn all pins off
          ug_stateofmcp23017 = 1
        else
          portsetvalue1 = 0x55
          HSerPrint hex(portsetvalue1)

          ' set ports status on MCP23017
          //!Here
          mcp23017_sendbyte(MCP23017_DEVICE_1, MCP23017_GPIOA, portsetvalue1 )' turn all pins on to state
          ug_stateofmcp23017 = 0
        end if
        HSerPrint "  "

      ANSI (  10, 40 )
      HSerPrint "Read Device  = "
      //!Here
            ' read ports status on MCP23008
      mcp23017_readbyte(MCP23017_DEVICE_1, MCP23017_GPIOA, ug_data )' read state


      if ug_stateofmcp23017 = 1 then
         HSerSend 27
         if ug_data <>  portsetvalue0  then
             HSerPrint "[1"
             HSerSend 0x3b
             HSerPrint "31m"

          else
             HSerPrint "[1"
             HSerSend 0x3b
             HSerPrint "32m"

          end if
      end if

      if ug_stateofmcp23017 = 0 then
         HSerSend 27
         if ug_data <> portsetvalue1  then
           HSerPrint "[1"
           HSerSend 0x3b
           HSerPrint "31m"
        else
           HSerPrint "[1"
           HSerSend 0x3b
           HSerPrint "32m"
        end if
      end if

      HSerPrint "0x"
      Hserprint hex(ug_data)
      Hserprint "    "
      HSerSend 27
      HSerPrint "[0m"


end sub

[mmotte]

David,

The library is in the include directory ..... GreatcowBasic/Include/mcp23017.h
GCB libraries end with '.h' but are the library not a header file.
It can be used by an include statement at the beginning of you code.

#include <mcp23017.h>

There is a demo file for another I2C expander under greatCowBasic/demos/I2C_solutions/I2C_serial_expanders/I2C_pcf8574_serial_expander..... .gcb

What processor will you be using? Just change the chip statement.

#chip mega328p, 16

GreatCowBasic has a very good Help page.
And use this forum to ask question. We are not usually grumpy like this past month.

GL
mike

[David Briscoe]

I'm agnostic about the chip at this stage (I'm using 16F819 or 16F1847 at the moment), but may choose a 18f series later on for the USB capability). I mainly use C (CCS C compiler) or assembly, but I've never used GCB. I've never used a MCP20317 or I2C either. I just want to start very simply with lighting 1 LED and then moving on to several LEDs and at the same time getting familiar with GCB. I guess reading the MCP23017.h file would help, but where does this header live?

[Anobium]

This is a really good read for someone new to Great Cow BASIC. https://sourceforge.net/p/gcbasic/discussion/579126/thread/d648215933/#825c

---

The headers are loaded into the include folder. So, you do not need to worry when you start.

#chip 16F1847
#include <mcp23017.h>

#DEFINE MCP23017_DEVICE_1 0X40   // address 0x40 the 8 bit address

 ; ----- Define I2C Hardware settings

   #define HI2C_BAUD_RATE 100
   #define HI2C_DATA PORTB.4    // required pullup 4k
   #define HI2C_CLOCK PORTB.6   // required pullup 4k

   Dir HI2C_DATA in
   Dir HI2C_CLOCK in

   HI2CMode Master
; ----- end of I2C Hardware settings

;main program
mcp23017_sendbyte(MCP23017_DEVICE_1, MCP23017_IODIRA  , 0x00)' turn all pins output

mcp23017_sendbyte(MCP23017_DEVICE_1, MCP23017_GPIOA, 0x00 )  //set all off
wait 1 s
mcp23017_sendbyte(MCP23017_DEVICE_1, MCP23017_GPIOA, 0xFF ) //set all on

This compiles. But, has not been tested.

However, does try to compile. You will get an error in the library there is a typo on line 191. All very obvious as HII2CStop should be HI2CStop(remove the II for I).

---

If this does work on the real hardware - you must try I2C discovery. This will confirm your setup. There are many I2C discover programs in your demos installation folder..

[David Briscoe]

Thanks everyone,
I'll give this a try over the next few weeks. If I come across any snags, I'll come back here for help.

David