GPIO Test Code

gistfile1.txt

pin=2

local function i2cInit()
-- init MCP23008 GPIO expander for led & pushbutton control
    i2c.setup(0,4,3,i2c.SLOW) --i2c init
    i2cWrite(0x00,0xe0) --0x00 IODIR, 0xf8 = 1110 0000 sets GPIO inputs and outputs
    i2cWrite(0x06,0xe0) --0x06 GPPU, 0xf8 = 1110 0000 sets GPIO pull up resistors
    i2cWrite(0x09,0xe0) --0x09 GPIO, 0xf8 = 1110 0000 inputs pins high, outputs pins low
    i2cWrite(0x02,0xe0) --0x02 GPINTEN, 0xe0 = 1110 0000 1=pin enable for interrupts
    i2cWrite(0x03,0xe0) --0x03 DEFVAL, 0xf8 = 1110 0000 values with no buttons pushed
    i2cWrite(0x04,0xff) --0x04 INTCON, 0xe0 = 1111 1111 compared against DEFVAL on interrupt
    --i2cWrite(0x05,0x28) --0x05 IOCON, 0xe8 = 0000 1000     
end

local function i2cRead(registerAddress)
--Reads byte from register
    local id=0
    i2c.start(id)
    i2c.address(id,32,i2c.TRANSMITTER) -- send MCP's address and write bit
    i2c.write(id,registerAddress)
    i2c.stop(id)
    i2c.start(id)
    -- Read the data form the register
    i2c.address(id,32,i2c.RECEIVER) -- send the MCP's address and read bit
    local data = 0x00
    data = i2c.read(id,1) -- we expect only one byte of data
    i2c.stop(id)
    return string.byte(data) -- i2c.read returns a string e convert to it's int value
end

function i2cWrite(registerAddress, data)
--Writes one byte (data) to a register, return void
    local id=0
    i2c.start(id)
    i2c.address(id,32,i2c.TRANSMITTER) -- send MCP's address and write bit
    i2c.write(id,registerAddress)
    i2c.write(id,data)
    i2c.stop(id)
end

local function IOInit()
    print("I/O Init")
    gpio.mode(pin, gpio.INT) -- GPIO 4 configured for interrupt mode
end

local function readi2c(level)
    local val = i2cRead(0x07)
    i2cRead(0x09)
    print(val)
end

i2cInit()
IOInit()

gpio.trig(pin, "low" , function(level) readi2c(level)  end)
--gpio.trig(pin, "low" , function(level) print("low")  end)
--gpio.trig(pin, "down" , function(level) print("down")  end)