Serial Module Initialization Sequence - Motorola MC68306 User Manual

6.5 SERIAL MODULE INITIALIZATION SEQUENCE

If the serial capability of the MC68306 is being used, the following steps are required to
properly initialize the serial module.
The serial module registers can be accessed by word or byte
operations, but only the data byte D7–D0 is valid.
Command Register (DUCR)
• Reset the receiver and transmitter for each channel.
The following steps program both channels:
Interrupt Vector Register (DUIVR)
• Program the vector number for a serial module interrupt.
Interrupt Mask Register (DUIMR)
• Enable the desired interrupt sources.
Auxiliary Control Register (DUACR)
• Select baud rate set (BRG bit).
• Initialize the input enable control (IEC bits).
• Select counter/timer mode and clock source if necessary.
Output Port Control Register (DUOPCR)
• Select the function of the output port pins.
The following steps are channel specific:
Clock Select Register (DUCSR)
• Select the receiver and transmitter clock.
Mode Register 1 (DUMR1)
• If desired, program operation of receiver ready-to-send (RxRTS bit).
• Select receiver-ready or FIFO-full notification (R/F bit).
• Select character or block error mode (ERR bit).
• Select parity mode and type (PM and PT bits).
• Select number of bits per character (B/Cx bits).
Mode Register 2 (DUMR2)
• Select the mode of channel operation (CMx bits).
• If desired, program operation of transmitter ready-to-send (TxRTS bit).
MOTOROLA
NOTE
MC68306 USER'S MANUAL 6-43