7.4.5 Fuse Programming

To write control or key fuses, an external supply of 2.5V ±10% DC 50 mA supply must be connected to VZC pin. The voltage in VZC must be applied only after the PL460 is already powered (11.8 Power On Considerations) and maintained during the entire fuse programming process. If fuses are programmed in the system, the appropriate protection of VZC circuitry by means of a 10K resistor must be implemented, as it is shown in the figure below.

Figure 7-2. Externally Fuse Programming Setup

The fuse programming commands are sent through SPI. In case of using an external fuses programming controller, the host MCU SPI ports must be left in High-Impedance mode to allow the connection between the PL460 and the external fuses programming controller.