S1C8F626 TECHNICAL MANUAL
EPSON
95
5 PERIPHERAL CIRCUITS AND THEIR OPERATION (Programmable Timer)
5.10.7 Transfer rate setting of serial interface
Since the underflow signal of the timer is divided
by 32 in the serial interface, the value set in the
register RDR1x/RDR7x which corresponds to the
transfer rate is shown in the following expression:
fdiv
RDR = ————— - 1
32
× bps
fdiv: Input clock frequency (setting of PST1x/PST7x)
bps: Transfer rate
The underflow signal of Timer 1/Timer 7 can be
used to clock the serial interface Ch.0/Ch.1.
The transfer rate setting in this case is made in the
registers PST1x/PST7x and RDR1x/RDR7x (since
only the underflow signal is used as the serial
interface clock source, the CDR1x/CDR7x register
value does not affect the transfer rates. It can be set
to any value).
Table 5.10.7.1 Example of transfer rate setting
Transfer rate
(bps)
19,200
9,600
4,800
2,400
1,200
600
300
150
PST1x/7x
00H
02H
RDR1x/7x
03H
07H
0FH
1FH
3FH
7FH
1FH
3FH
PST1x/7x
00H
03H
RDR1x/7x
04H
09H
13H
27H
4FH
9FH
09H
13H
PST1x/7x
00H
01H
02H
RDR1x/7x
05H
0BH
17H
2FH
5FH
BFH
5FH
fOSC3 = 2.4576 MHz
fOSC3 = 3.0720 MHz
fOSC3 = 3.6864 MHz
OSC3 oscillation frequency / Programmable timer settings
Since the underflow signal only is used as the clock source, the
CDR1x/CDR7x register value does not affect the transfer rates.
5.10.8 Setting frame frequency for LCD driver
The underflow signal of Timer 5 can be used as the
source clock to generate the frame signal for the
LCD driver.
The frame frequency is set up using the registers
PST5x and RDR5x (since only the underflow signal
is used as the source clock, the CDR5x register
value does not affect the frame signal. It can be set
to any value).
The Timer 5 underflow signal is divided by 128 (for
1/16 or 1/3 duty) or 256 (for 1/8 duty) in the LCD
driver, so set a value represented by the following
expressions to the register RDR5x.
(for 1/16 or 1/32 duty)
fdiv
RDR5x = ————— - 1
128
× fFRM
(for 1/8 duty)
fdiv
RDR5x = ————— - 1
256
× fFRM
fdiv: Input clock frequency (setting of PST5x)
fFRM: Frame frequency (Hz)