Specifications

Serial Communications (V40)
Programming
The SCU is enabled and mapped into an I/O address range using the
V40 Configuration register. The SCU includes four programmable
registers. The steps listed below outline the procedure for
programming the SCU for serial operation. The steps include
initializing counter/timer 1 to generate the baud rate.
1. Program the TCKS V40 configuration register for counter/timer
1 to use the internal clock divided by two. Note that an external
clock or another divisor can be used, but the baud rate counts
shown in Table 10-3 must be adjusted.
2. Program the TMD register of the TCU for binary count, square
wave generation (mode 3), low byte followed by high byte, and
selection of TCT1.
3. Program the TCT1 Count register of the TCU with the selected
baud rate. Use a two-byte output operation — low byte followed
by high byte.
4. Program the SMD register of the SCU with the selected baud
factor, character and stop bit length, and parity selection.
5. Program the SCM and SIMK registers for the desired operation.
10-16