MSM66591 Datasheet, PDF (256/466 Pages) OKI electronic componets – CMOS 16-bit microcontroller

MSM66591/ML66592 User's Manual
Chapter 14 Baud Rate Generator Functions
14.6 Operation of SCI2 Timer
Basically the SCI2 timer operates as an auto reload timer. If the 8-bit SCI2 timer
counter overflows, the value of the 8-bit SCI2 timer register is loaded to the counter. At
the same time, an interrupt request by overflow is generated. The calculation of the
baud rate when SCI2 is used as the baud rate generator is shown below.
B
= f_(BRG) ¥
1
256 – D
Â¥
1
16
B: baud rate
f_(BRG): S2TM count clock frequency (Hz)
D: reload value (0 to 255)
Even if the reload value is written to the SCI2 timer register, the content of the SCI2
timer counter does not change. If the SCI2 timer is used as the auto reload timer (baud
rate generator) from the beginning of an operation, it is necessary to write the same
value to both the SCI2 timer counter and SCI2 timer register through programming.
14
14-11