Driver with built-in self testing of switch status

Methods and devices for reading and programming a state of a switch device are presented. Reading of the state is provided by measuring a resistance of the switch via injection of a current. If a measured resistance does not correspond to a resistance of an expected state, then the switch is reprogrammed, and the state reread. The switch device may form part of a complex switch circuit that includes a combination of shunt and through switch devices. Currents injected into external loads coupled to the switch circuit increase accuracy in reading of the state. Further accuracy in reading of the state of a through switch device is provided by provision of a bypass path to a shunt switch device. The complex switch circuit may be implemented as a SPDT switch including two branches, each branch including a shunt and a through switch device. Several types of switch devices, such as phase-change material (PCM) devices may be implemented.