S1C63454 TECHNICAL MANUAL
EPSON
67
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Programmable Timer)
CHSEL: TOUT output channel selection register (FFC1H•D3)
Selects the channel used for TOUT signal output.
When "1" is written: Timer 1
When "0" is written: Timer 0
Reading: Valid
This register selects which timer's underflow (timer 0 or timer 1) is used to generate a TOUT signal. When
"0" is written to the CHSEL register, timer 0 is selected and when "1" is written, timer 1 is selected.
At initial reset, this register is set to "0".
PTOUT: TOUT output control register (FFC1H•D2)
Turns TOUT signal output ON and OFF.
When "1" is written: ON
When "0" is written: OFF
Reading: Valid
PTOUT is the output control register for the TOUT signal. When "1" is written to the register, the TOUT
signal is output from the output port terminal R02 and when "0" is written, the terminal goes to a high
(V
DD
) level. However, the data register R02 must always be "1" and the high impedance control register
R02HIZ must always be "0" (data output state).
At initial reset, this register is set to "0".
EIPT0: Timer 0 interrupt mask register (FFE2H•D0)
EIPT1: Timer 1 interrupt mask register (FFE2H•D1)
These registers are used to select whether to mask the programmable timer interrupt or not.
When "1" is written: Enabled
When "0" is written: Masked
Reading: Valid
Timer 0 and timer 1 interrupts can be masked individually by the interrupt mask registers EIPT0 (timer 0)
and EIPT1 (timer 1).
At initial reset, these registers are set to "0".
IPT0: Timer 0 interrupt factor flag (FFF2H•D0)
IPT1: Timer 1 interrupt factor flag (FFF2H•D1)
These flags indicate the status of the programmable timer interrupt.
When "1" is read: Interrupt has occurred
When "0" is read: Interrupt has not occurred
When "1" is written: Flag is reset
When "0" is written: Invalid
The interrupt factor flags IPT0 and IPT1 correspond to timer 0 and timer 1 interrupts, respectively. The
software can judge from these flags whether there is a programmable timer interrupt. However, even if
the interrupt is masked, the flags are set to "1" by the underflows of the corresponding counters.
These flags are reset to "0" by writing "1" to them.
After an interrupt occurs, the same interrupt will occur again if the interrupt enabled state (I flag = "1") is
set or the RETI instruction is executed unless the interrupt factor flag is reset. Therefore, be sure to reset
(write "1" to) the interrupt factor flag in the interrupt service routine before shifting to the interrupt
enabled state.
At initial reset, these flags are set to "0".
Содержание S1C63454
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