Master/slave control of touch sensing

A touch sensing system comprising:

• a touch sensing surface including first and second drive lines, and first and second sense lines;
• a master controller that applies one or more drive signals to the first drive lines and receives one or more sense signals from the first sense lines;
• a slave controller that applies one or more drive signals to the second drive lines and receives one or more sense signals from the second sense lines, wherein the sense signals received by the master controller and slave controller include one or more sense signals that include a superposition of signals resulting from drive signals applied by the master and slave controllers;
• a communication link between the master controller and the slave controller;
• and
• one or more processors that process touch information of the sense signals to sense a touch on or near the touch sensing surface.

A method of training communication between a master controller and a slave controller for joint operation of a touch sensing surface, the method comprising:

• transmitting a first clock signal from the master controller to the slave controller;
• transmitting a first command from the master controller to the slave controller, the first command including sequence information;
• and
• initiating a communication sequence in the slave controller, the communication sequence based on the first clock signal and the sequence information, wherein the receives communications from the master during a first portion of the communication sequence, and the slave controller transmits communications to the master during a second portion of the communication sequence.