I/O Memory Of Clock Timer - Epson S1C63558 Technical Manual

4.8.4 I/O memory of clock timer

Table 4.8.4.1 shows the I/O addresses and the control bits for the clock timer.
Register
Address
D3 D2
0 0 TMRST TMRUN
FF78H
R
TM3 TM2
FF79H
R
TM7 TM6
FF7AH
R
EIT3 EIT2
FFE6H
R/W
IT3 IT2
FFF6H
R/W
*1 Initial value at initial reset
*2 Not set in the circuit
*3 Constantly "0" when being read
TM0–TM7: Timer data (FF79H, FF7AH)
The 128–1 Hz timer data of the clock timer can be read out with these registers. These eight bits are read
only, and writing operations are invalid.
By reading the low-order data (FF79H), the high-order data (FF7AH) is held until reading or for 0.48–1.5
msec (one of shorter of them).
At initial reset, the timer data is initialized to "00H".
TMRST: Clock timer reset (FF78H•D1)
This bit resets the clock timer.
When "1" is written: Clock timer reset
When "0" is written: No operation
Reading: Always "0"
The clock timer is reset by writing "1" to TMRST. When the clock timer is reset in the RUN status, opera-
tion restarts immediately. Also, in the STOP status the reset data is maintained. No operation results
when "0" is written to TMRST.
This bit is write-only, and so is always "0" at reading.
TMRUN: Clock timer RUN/STOP control register (FF78H•D0)
Controls RUN/STOP of the clock timer.
When "1" is written: RUN
When "0" is written: STOP
Reading: Valid
The clock timer enters the RUN status when "1" is written to the TMRUN register, and the STOP status
when "0" is written. In the STOP status, the timer data is maintained until the next RUN status or the
timer is reset. Also, when the STOP status changes to the RUN status, the data that is maintained can be
used for resuming the count.
At initial reset, this register is set to "0".
S1C63558 TECHNICAL MANUAL
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Clock Timer)
Table 4.8.4.1 Control bits of clock timer
D1 D0 Name Init 1
3 2
0 –
0 3 – 2
3
TMRST Reset
W R/W
TMRUN 0
TM3 0
TM1 TM0
TM2 0
TM1 0
TM0 0
TM7 0
TM5 TM4
TM6 0
TM5 0
TM4 0
EIT3 0
EIT1 EIT0
EIT2 0
EIT1 0
EIT0 0
IT3 0
IT1 IT0
IT2 0
IT1 0
IT0 0
1 0
Unused
Unused
Reset Invalid Clock timer reset (writing)
Run Stop Clock timer Run/Stop
Clock timer data (16 Hz)
Clock timer data (32 Hz)
Clock timer data (64 Hz)
Clock timer data (128 Hz)
Clock timer data (1 Hz)
Clock timer data (2 Hz)
Clock timer data (4 Hz)
Clock timer data (8 Hz)
Enable Mask Interrupt mask register (Clock timer 1 Hz)
Enable Mask
Interrupt mask register (Clock timer 2 Hz)
Enable Mask Interrupt mask register (Clock timer 8 Hz)
Enable Mask Interrupt mask register (Clock timer 32 Hz)
(R) (R)
Interrupt factor flag (Clock timer 1 Hz)
Yes No Interrupt factor flag (Clock timer 2 Hz)
(W) (W)
Interrupt factor flag (Clock timer 8 Hz)
Reset Invalid Interrupt factor flag (Clock timer 32 Hz)
EPSON
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