-- Kitt Car Modified by John Longworth November 2017
-- Using pins 3 & 4 to be compatible with ESP001

id=0
sda = 3  -- 1 ~ 12  IO index 
scl = 4  -- 1 ~ 12  IO index 
i2c.setup(id, sda, scl, i2c.SLOW)  -- Initialize I2C

function read_reg(dev_addr, reg_addr)
    i2c.start(id)
    i2c.address(id, dev_addr ,i2c.TRANSMITTER)
    i2c.write(id,reg_addr)
    i2c.stop(id)
    i2c.start(id)
    i2c.address(id, dev_addr,i2c.RECEIVER)
    c=i2c.read(id,1)
    i2c.stop(id)
    return c
end

function write_reg(dev_addr, reg_addr, reg_val)
    i2c.start(id)
    i2c.address(id, dev_addr, i2c.TRANSMITTER)
    i2c.write(id, reg_addr)
    i2c.write(id, reg_val)
    i2c.stop(id)
end

write_reg(0x20, 0x00, 0x00) -- set bank A to output
i = 1
dir = 1

tmr.alarm(0,250,1,function() 
    write_reg(0x20, 0x12, i) 
    --print("I = " .. i)
    dir = (i == 1) and (dir == -1) and 1 or (i == 128) and (dir == 1) and -1 or dir
    i = (dir == 1) and i * 2 or i / 2
end)

-- Pin Connections on my board
-- Pin 9  (VDD) to 3v3
-- Pin 10 (VSS) to GND
-- Pin 11 (NC) to GND (Not necessary)
-- Pin 12 (SCL) to ESP GPIO2
-- Pin 13 (SDA) to ESP GPIO0
-- Pin 14 (NC) to GND (Not necessary)
-- Pin 15 (A0) to GND
-- Pin 16 (A1) to GND
-- Pin 17 (A2) to GND
-- Pin 18 (RESET) to 3v3
-- Connect pins to be read to Gnd on Port B