7 transfer rate setting of serial interface, 8 setting frame frequency for lcd driver – Epson S1C88650 User Manual
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EPSON
S1C88650 TECHNICAL MANUAL
5 PERIPHERAL CIRCUITS AND THEIR OPERATION (Programmable Timer)
5.10.7 Transfer rate setting of serial interface
Since the underflow signal of Timer 1 is divided by
32 in the serial interface, the value set in the
register RDR1X which corresponds to the transfer
rate is shown in the following expression:
fdiv
RDR1X = ————— - 1
32
×
bps
fdiv: Input clock frequency (setteing of PST1X)
bps: Transfer rate
The underflow signal of Timer 1 can be used to
clock the serial interface.
The transfer rate setting in this case is made in the
registers PST1X and RDR1X (since only the
underflow signal is used as the serial interface clock
source, the CDR1X 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
00H
00H
00H
00H
00H
00H
02H
02H
RDR1X
03H
07H
0FH
1FH
3FH
7FH
1FH
3FH
PST1X
00H
00H
00H
00H
00H
00H
03H
03H
RDR1X
04H
09H
13H
27H
4FH
9FH
09H
13H
PST1X
00H
00H
00H
00H
00H
00H
01H
02H
RDR1X
05H
0BH
17H
2FH
5FH
BFH
BFH
5FH
f
OSC3
= 2.4756 MHz
f
OSC3
= 3.0720 MHz
f
OSC3
= 3.6864 MHz
OSC3 oscillation frequency / Programmable timer settings
∗
Since the underflow signal only is used as the clock source, the CDR1X
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
×
f
FRM
(for 1/8 duty)
fdiv
RDR5X = ————— - 1
256
×
f
FRM
fdiv: Input clock frequency (setteing of PST5X)
f
FRM
: Frame frequency (Hz)