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CHAPTER 7 8-BIT PWM TIMER
Table 7.3-1 PWM 1 Control Register (CNTR1) bit
Bit
Function
Bit 7
P/TX:
Operating mode
selection bit
This bit switches between the interval timer function (P/
TX = "0") and PWM timer function (P/TX = "1").
Check:
Write to this bit when the counter operation is stopped
(TPE = "0"), interrupts are disabled (TIE = "0"), and the
interrupt request flag bit is cleared (TIR = "0").
Bit 6
Unused bit
The read value is indeterminate.
Writing to this bit has no effect on the operation.
Bit 5
Bit 4
P1, P0:
Clock selection bit
These bits select the count clock for the interval timer
function and PWM timer function.
These bits can select the count clock from three internal
count clocks or the output cycle of the timer 1.
If the timer 1 output is selected, operate the 8/16-bit
timer/counter in 8-bit mode.
Check:
Do not change P1 and P0 when the counter is operating
(TPE = "1").
Bit 3
TPE:
Counter operation
enable bit
This bit activates or stops operation of the PWM timer
function and interval timer function.
Writing "1" to this bit starts the count operation. Writing
"0" to this bit stops the count and clears the counter to
"00H".
Bit 2
TIR:
Interrupt request
flag bit
For the interval timer function:
This bit is set to "1" when the counter and PWM 1
compare register (COMR1) values match.
An interrupt request is output to the CPU when both this
bit and the interrupt request enable bit (TIE) are "1".
For the PWM timer function:
Interrupt requests are not generated.
Writing "0" clears this bit. Writing "1" has no effect and
does not change the bit value.
Bit 1
OE:
Output pin control
bit
The P30/PWM1/BZ pin functions as a general-purpose
port (P30) or Buzzer output when this bit is set to "0"
and a dedicated pin (PWM1) when this bit is set to "1".
The PWM1 pin outputs a square wave when the interval
timer function is selected and a PWM waveform when
the PWM timer function is selected.
Bit 0
TIE:
Interrupt request
enable bit
This bit enables or disables and an interrupt request output
to the CPU. An interrupt request is output when both this bit
and the interrupt request flag bit (TIR) are "1".