Epson S1C63558 EVCNT: Timer 0 counter mode selection register (FFC0H•D2), CKSEL0: Prescaler 0 source clock selection register (FFC1H•D0)

CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Programmable Timer)

CKSEL0: Prescaler 0 source clock selection register (FFC1H•D0)CKSEL1: Prescaler 1 source clock selection register (FFC1H•D1)

Selects the source clock of the prescaler.

When "1" is written: OSC3 clock

When "0" is written: OSC1 clock

Reading: Valid

The source clock for the prescaler is selected from OSC1 or OSC3. When "0" is written to the CKSEL0 register, the OSC1 clock is selected as the input clock for the prescaler 0 (for timer 0) and when "1" is written, the OSC3 clock is selected.

Same as above, the source clock for prescaler 1 is selected by the CKSEL1 register.

When the event counter mode is selected to timer 0, the setting of the CKSEL0 register becomes invalid. At initial reset, these registers are set to "0".

PTPS00, PTPS01: Timer 0 prescaler division ratio selection register (FFC2H•D2, D3)

PTPS10, PTPS11: Timer 1 prescaler division ratio selection register (FFC3H•D2, D3)

Selects the division ratio of the prescaler.

Two bits of PTPS00 and PTPS01 are the prescaler division ratio selection register for timer 0, and two bits of PTPS10 and PTPS11 are for timer 1. The prescaler division ratios that can be set by these registers are shown in Table 4.10.8.2.

Table 4.10.8.2 Selection of prescaler division ratio

PTPS11	PTPS10	Prescaler division ratio
PTPS01	PTPS00
1	1	Source clock / 256
1	0	Source clock / 32
0	1	Source clock / 4
0	0	Source clock / 1

When the event counter mode is selected to timer 0, the setting of the PTPS00 and PTPS01 becomes invalid.

At initial reset, these registers are set to "0".

EVCNT: Timer 0 counter mode selection register (FFC0H•D2)

Selects a counter mode for timer 0.

When "1" is written: Event counter mode

When "0" is written: Timer mode

Reading: Valid

The counter mode for timer 0 is selected from either the event counter mode or timer mode. When "1" is written to the EVCNT register, the event counter mode is selected and when "0" is written, the timer mode is selected.

At initial reset, this register is set to "0".

72 EPSON S1C63558 TECHNICAL MANUAL