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S1C63454 TECHNICAL MANUAL
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Programmable Timer)
RLD00–RLD07: Timer 0 reload data register (FFC4H, FFC5H)
RLD10–RLD17: Timer 1 reload data register (FFC6H, FFC7H)
Sets the initial value for the counter.
The reload data written in this register is loaded to the respective counters. The counter counts down
using the data as the initial value for counting.
Reload data is loaded to the counter when the counter is reset by writing "1" to the PTRST0 or PTRST1
register, or when counter underflow occurs.
At initial reset, these registers are set to "00H".
PTD00–PTD07: Timer 0 counter data (FFC8H, FFC9H)
PTD10–PTD17: Timer 1 counter data (FFCAH, FFCBH)
Count data in the programmable timer can be read from these latches.
The low-order 4 bits of the count data in timer 0 can be read from PTD00–PTD03, and the high-order data
can be read from PTD04–PTD07. Similarly, for timer 1, the low-order 4 bits can be read from PTD10–
PTD13, and the high-order data can be read from PTD14–PTD17.
Since the high-order 4 bits are held by reading the low-order 4 bits, be sure to read the low-order 4 bits
first.
Since these latches are exclusively for reading, the writing operation is invalid.
At initial reset, these counter data are set to "00H".
PTRST0: Timer 0 reset (reload) (FFC2H•D1)
PTRST1: Timer 1 reset (reload) (FFC3H•D1)
Resets the timer and presets reload data to the counter.
When "1" is written: Reset
When "0" is written: No operation
Reading: Always "0"
By writing "1" to PTRST0, the reload data in the reload register PLD00–PLD07 is preset to the counter in
timer 0. Similarly, the reload data in PLD10–PLD17 is preset to the counter in timer 1 by PTRST1.
When the counter is preset in the RUN status, the counter restarts immediately after presetting. In the
case of STOP status, the reload data is preset to the counter and is maintained.
No operation results when "0" is written.
Since these bits are exclusively for writing, always set to "0" during reading.
PTRUN0: Timer 0 RUN/STOP control register (FFC2H•D0)
PTRUN1: Timer 1 RUN/STOP control register (FFC3H•D0)
Controls the RUN/STOP of the counter.
When "1" is written: RUN
When "0" is written: STOP
Reading: Valid
The counter in timer 0 starts counting down by writing "1" to the PTRUN0 register and stops by writing
"0".
In STOP status, the counter data is maintained until the counter is reset or is set in the next RUN status.
When STOP status changes to RUN status, the data that has been maintained can be used for resuming
the count.
Same as above, the timer 1 counter is controlled by the PTRUN1 register.
At initial reset, these registers are set to "0".
