-- John Longworth December 2017
-- Set time on an external RTC
-- Uses I2C module
-- NOTE: time is stored in BCD format (base 16)

local id, sda, scl, device = 0, 3, 4, 0x68
i2c.setup(id, sda, scl, i2c.SLOW)

i2c.start(id)
i2c.address(id, device, i2c.TRANSMITTER)
i2c.write(id, 0)
i2c.write(id, tonumber(0,16))   -- seconds
i2c.write(id, tonumber(59,16))  -- minutes
i2c.write(id, tonumber(23,16))  -- hours
i2c.write(id, tonumber(6,16))   -- wday
i2c.write(id, tonumber(31,16))  -- day
i2c.write(id, tonumber(12,16))  -- month
i2c.write(id, tonumber(17,16))  -- year
i2c.stop(id)

-- Set time to 23:59:00 - Day 6 on 31/12/2017