12.2.4.4.2 NRZ to RZI Modulation
The NRZ to RZI modulation receives the MMUART_X_TXD_nrz signal which is in NRZ format and needs to be converted into the RZI format. The modulator waits for a negative edge on the NRZ signal, sets a baud rate/16 decremented down counter and outputs a pulse for the first 3 or 4 counts. If the count reaches zero and the NRZ signal is still Low, another output pulse is generated, otherwise, no pulse is generated.
The output of the modulator can be an inverted version of the following figure with the EITX configuration bit in the Table 12-23. Additionally, the output can be 1/4 widths instead of 3/16th using the EITP bit. Also the EIRD (enable bit RZI mod/demod) bit in Table 12-23 has to be enabled. The following example shows an output for a signal that has two consecutive zeros and the value of EIRD=1, EITX=1, and EITP=0.
