4.4 TPI Interface
The Tiny Programming Interface is featured on the tinyAVR® devices with the lowest pin count.
The following figure shows the standard TPI connector supplied along with the Microchip programmer device. Only three pins on the device are required for use of this interface; RESET, TPICLK, and TPIDATA. The latter two pins are multiplexed with regular I/O pins.
The RESET pin can be reconfigured as an I/O pin by programming the RSTDISBL
fuse of the device. This disables the reset functionality and requires +12V to be
applied to Reset for programming to work. Only a few programming tools are capable of
generating this voltage.
Note: Refer to
the respective programmer user guide for more information about the capabilities and
physical interface of TPI.