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CHAPTER 7 8-BIT PWM TIMER
7.8
States in Each Mode during 8-bit PWM Timer Operation
This section describes the operation of the 8-bit PWM timer when the device changes
to sleep or stop mode or an operation halt request occurs during operation.
s Operation during Standby Mode or Operation Halt
Figure 7.8-1 "Counter Operation during Standby Modes or Operation Halt (For Interval Timer
Function)" and 7.8-2 "Operation during Standby Modes or Operation Halt (For PWM Timer
Function)" show the counter value states when the device changes to sleep or stop mode, or an
operation halt request occurs, during operation of the interval timer function or PWM timer
function.
The counter halts and maintains its current value when the device changes to stop mode.
Operation starts again from the stored counter value after wake-up from stop mode by an
external interrupt. Therefore, the first interval time or PWM wave cycle does not match the set
value. Always initialize the 8-bit PWM timer after wake-up from stop mode.
r For interval timer function
Figure 7.8-1 Counter Operation during Standby Modes or Operation Halt (For Interval Timer Function)
Counter value
COMR value (FFH)
FFH
00H
Timer cycle
Time
TIR bit
TPE bit
PTO pin
SLP bit
Cleared by the program
Stop request
Oscillation
stabilization delay time
Cleared by the operation halt.
Operation halts
Operation restarts
(OE = "1")
(STBC register)
STP bit
(STBC register)
Sleep mode
Wake-up from sleep mode by IRQ9 or IRQA.
"L" while conter is stopped.
*
Stop mode
Wake-up from stop mode by an external interrupt.
* : The PWM pin (PWM1, PWM2) goes to the high-impedance state during stop mode if the pin state
specification bit in the standby control register (STBC: SPL) is "1" and the PWM pin is not set to with a pull-
up resistor (unless the pin is pulled up, a pull-up option selectable for the PWM2 pin only).
When the SPL bit is "0", the pin maintains its value prior to changing to stop mode.