Epson S1C63666 Technical Manual page 93

4.11.8 Transfer rate setting for serial interface
The signal that is made from underflows of timer 2 by dividing them in 1/2, can be used as the clock
source for the serial interface.
The programmable timer outputs the clock to the serial interface by setting timer 2 into RUN state
(PTRUN2 = "1"). It is not necessary to control with the PTOUT register.
PTRUN2
Timer 2 underflow
Source clock for serial I/F
A setting value for the RLD2x register according to a transfer rate is calculated by the following expres-
sion:
RLD2x = fosc / (2 ∗ bps ∗ division ratio of the prescaler) - 1
fosc: Oscillation frequency (OSC1/OSC3)
bps: Transfer rate
(00H can be set to RLD2x)
Be aware that the maximum clock frequency for the serial interface is limited to 1 MHz when OSC3 is
used as the clock source.
S1C63666 TECHNICAL MANUAL
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Programmable Timer)
Fig. 4.11.8.1 Synchronous clock of serial interface
EPSON
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