21.4 Physical Layer of Tiny Programming Interface

The TPI physical layer handles the basic low-level serial communication. The TPI physical layer uses a bi-directional, half-duplex serial receiver and transmitter. The physical layer includes serial-to-parallel and parallel-to-serial data conversion, start-of-frame detection, frame error detection, parity error detection, parity generation and collision detection.

The TPI is accessed via three pins, as follows:
  • RESET: Tiny Programming Interface enable input
  • TPICLK: Tiny Programming Interface clock input
  • TPIDATA: Tiny Programming Interface data input/output

In addition, the VCC and GND pins must be connected between the external programmer and the device.