Datasheet

Jon Waddington

contain the house code and the 4 least significant bits contain the device code or the

function code.

The checksum is calculated by calculating the sum of the first 2 bytes. This is then

transmitted to the Propeller which confirms that the data is correct by transmitting an

acknowledge byte of ‘0x00’. When the CM12 is ready to receive again it transmits ‘0x55’

to the Propeller.

The SPIN code below shows a method which handles the full transmission with the CM12

controller. The device code and function code are passed into the method and the

Simple_Serial object is used to transmit and receive the signals from the CM12.

PUB do(device, function) | rx

{method to perform a function on X10 devices}

repeat until rx == (($04 + (housecode + device))& $FF) 'repeat until correct

checksum received

serial.tx($04) 'transmit header

serial.tx(housecode + device) 'transmit code

rx := serial.rx 'receive checksum

if rx == $A5 'if controller is polling system

serial.tx($C3) 'respond to polling

serial.tx($00) 'send acknowledgement of checksum

repeat until rx == $55 'wait until 'ready to receive' is received

rx := serial.rx

repeat until rx == (($06 + (housecode + function))& $FF) 'repeat until correct

checksum received

serial.tx($06) 'transmit code

serial.tx(housecode + function) 'transmit code

rx := serial.rx 'receive checksum

serial.tx($00) 'send acknowledgement of checksum

repeat until rx := $55 'wait until 'ready to receive' is received

rx := serial.rx

When the CM12 receives data from the power-line, it begins to poll the Propeller to

upload its buffer. The poll signal is a byte (0xA5) which is transmitted once every second

until the Propeller responds by transmitting a byte with the value of ‘0xC3’. While the

CM12 is polling the Propeller, a transmission cannot take place.

Figure 3.4.3.2 shows the binary house codes and address codes which are assigned to

the X10 devices [33]. Figure 3.4.3.3 shows the binary function codes which are

transmitted to the previously addressed X10 device to perform a desired function [33].