SLOS758G December 2011 – March 2020 TRF7963A
PRODUCTION DATA.
After power-up and the EN pin low-to-high transition, the registers are in a default mode, which must be changed by writing the desired ISO protocol settings to the ISO Control register. The low-level option registers (0x02 to 0x0B) are automatically configured to the new protocol parameters. After selecting the protocol, it is possible to change some low-level register contents if needed. However, changing to another protocol and then back reloads the default settings; therefore, the custom settings must be reloaded.
The Clo0 and Clo1 bits in the Modulator and SYS_CLK Control register (0x09), which define the microcontroller frequency available on the SYS_CLK pin, are the only 2 bits in the configuration registers that are not cleared during protocol selection.