SLOS758G December 2011 – March 2020 TRF7963A
PRODUCTION DATA.
The digital part of the transmitter is a mirror of the receiver. The settings controlled the ISO Control register (0x01) are applied to the transmitter just like the receiver. In the TRF7963A default mode (ISO Mode), the TRF7963A automatically adds all the special signals like start of communication, end of communication, SOF, EOF, parity bits and CRC bytes.
The data is then coded to modulation pulse levels and sent to the RF output stage modulation control unit. Just like with the receiver, this means that the external system MCU only must load the FIFO with data and all the microcoding is done automatically, again saving the firmware developer code space and time. Additionally, all the registers used for transmit parameter control are automatically preset to optimum values when a new selection is entered into the ISO Control register (0x01).
NOTE
The FIFO must be reset before starting any transmission with direct command 0x0F.
There are two ways to start the transmit operation:
NOTE
If the data length is longer than the FIFO, the external system MCU is warned when the majority of data from the FIFO was already transmitted by sending and interrupt request with flag in IRQ register to indicate a FIFO low or high status. The external system should respond by loading next data packet into the FIFO.
At the end of a transmit operation, the external system MCU is notified by interrupt request (IRQ) with a flag in the IRQ register (0x0C) indicating TX is complete (example value = 0x80).
The TX Length registers also support incomplete byte transmission. The high two nibbles in register 0x1D and the nibble composed of bits B4 to B7 in register 0x1E store the number of complete bytes to be transmitted. Bit B0 in register 0x1E is a flag indicating that there are also additional bits to be transmitted which do not form a complete byte. The number of bits is stored in bits B1 to B3 of the same register (0x1E).
Some protocols have options so there are two sublevel configuration registers to select the TX protocol options.