II-36
EPSON
S1C62740 TECHNICAL SOFTWARE
CHAPTER 6: PERIPHERAL CIRCUITS (Clock Timer)
Clock Timer
6.7
I/O data memory of
the clock timer
The control registers of the clock timer are shown in Table 6.7.1.
Table 6.7.1 Control registers of clock timer
*1 Initial value at the time of initial reset
*5 Constantly "0" when being read
*2 Not set in the circuit
*6 Refer to main manual
*3 Undefined
*7 Page switching in I/O memory is not necessary
*4 Reset (0) immediately after being read
Control of the clock
timer
S1C62740 has a clock timer with OSC1 (crystal oscillation) as
basic oscillation built-in.
Clock timer data
The 128–1 Hz timer data of the clock timer can be read out with
TM0–TM7 registers (E3H and E4H).
Clock timer reset
By writing "1" on TMRST (E2HD0), the clock timer is reset and all
timer data are set to "0".
Timer interrupt
The clock timer interrupt is generated at the falling edge of the
frequencies (32 Hz, 8 Hz, 2 Hz and 1 Hz). At this time, the corre-
sponding interrupt factor flag (IT32, IT8, IT2 and IT1) is set to "1".
Selection of whether to mask the separate interrupts can be made
with the interrupt mask registers (EIT32, EIT8, EIT2 and EIT1).
Address
Comment
Register
D3
D2
D1
D0
Name
Init
1
0
*1
C6H
IT32
R
IT1
IT2
IT8
IT32
0
Interrupt factor flag (clock timer 1 Hz)
Interrupt factor flag (clock timer 2 Hz)
Interrupt factor flag (clock timer 8 Hz)
Interrupt factor flag (clock timer 32 Hz)
Yes
No
IT8
IT2
IT1
*4
*7
CCH
EIT32
EIT1
EIT2
EIT8
EIT32
0
Enable
Mask
EIT8
EIT2
EIT1
R/W
Interrupt mask register (clock timer 1 Hz)
Interrupt mask register (clock timer 2 Hz)
Interrupt mask register (clock timer 8 Hz)
Interrupt mask register (clock timer 32 Hz)
E2H
TMRST
W
0
TMRST
Reset
–
0
–
*2
*5
TM0
R
TM3
TM2
TM1
TM0
–
TM1
TM2
TM3
E3H
*3
Unused
Clock timer and watchdog timer reset
Clock timer data (16 Hz)
Clock timer data (32 Hz)
Clock timer data (64 Hz)
Clock timer data (128 Hz)
R
TM4
R
TM7
TM6
TM5
TM4
–
TM5
TM6
TM7
E4H
*3
Clock timer data (1 Hz)
Clock timer data (2 Hz)
Clock timer data (4 Hz)
Clock timer data (8 Hz)