9 ClOCK TiMeR
S1C63003/004/008/016 TeChniCal Manual
Seiko epson Corporation
9-3
(Rev. 1.1)
Address
Register name R/W Default
Setting/data
Function
FF41H D3
TM3
R
0
0H–FH
Clock timer data (16 Hz)
D2
TM2
R
0
Clock timer data (32 Hz)
D1
TM1
R
0
Clock timer data (64 Hz)
D0
TM0
R
0
Clock timer data (128 Hz)
FF42H D3
TM7
R
0
0H–FH
Clock timer data (1 Hz)
D2
TM6
R
0
Clock timer data (2 Hz)
D1
TM5
R
0
Clock timer data (4 Hz)
D0
TM4
R
0
Clock timer data (8 Hz)
*
1 Initial value at initial reset
*
2 Not set in the circuit
*
3 Constantly "0" when being read
*
4 Unused in the S1C63003/004/008
*
5 Unused in the S1C63003/004
*
6 Unused in the S1C63003
RTCKe: Clock timer clock enable register (FF16h•D0)
Controls the operating clock supply to the clock timer.
When "1" is written: On
When "0" is written: Off
Reading: Valid
When "1" is written to RTCKE, the clock timer operating clock is supplied from the clock manager. If it is not
necessary to run the clock timer, stop the clock supply by setting RTCKE to "0" to reduce current consumption.
At initial reset, this register is set to "0."
TMRun: Clock timer Run/Stop control register (FF40h•D0)
Controls run/stop of the clock timer.
When "1" is written: Run
When "0" is written: Stop
Reading: Valid
The clock timer starts running when "1" is written to the TMRUN register, and stops when "0" is written. In stop
status, the timer data is maintained until the next run status or the timer is reset. Also, when stop status changes
to run status, the data that is maintained can be used for resuming the count. At initial reset, this register is set to
"0."
TMRST: Clock timer reset (FF40h•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. The clock timer must be reset when it is stopped (TMRUN =
"0"). No operation results when "0" is written to TMRST. This bit is write-only, and so is always "0" at reading.
TM[7:0]: Timer data (FF42h, FF41h)
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 (FF41H), the high-order data (FF42H) is latched.
The latched value, not the current value, is always read as the high-order data. Therefore, be sure to read the low-
order data first. At initial reset, the timer data is initialized to "00H."