-- John Longworth December 2017
-- Write a byte to EEPROM and read back data
-- Uses I2C module

local id, sda, scl, device = 0, 3, 4, 0x50
i2c.setup(id, sda, scl, i2c.SLOW)  -- Initialise I2C 
memloc = 0x01

addrh=bit.rshift(memloc, 8)
addrl=bit.band(memloc, 0xff)

-- Write to memory location
i2c.start(id)
i2c.address(id, device, i2c.TRANSMITTER)
i2c.write(id, addrh)
i2c.write(id, addrl)
i2c.write(id,string.byte("T"))
i2c.stop(id)

tmr.delay(5000)

-- Read from memory location
i2c.start(id)
i2c.address(id, device, i2c.TRANSMITTER)
i2c.write(id, addrh)
i2c.write(id, addrl)
i2c.stop(id)
i2c.start(id)
i2c.address(id, device, i2c.RECEIVER)
print("The contents of "..memloc.." = "..i2c.read(id, 1))
i2c.stop(id)