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CHAPTER 7 8-BIT PWM TIMER
7.1 Overview of 8-bit PWM Timer

An 8-bit PWM timer has the interval timer functions and the PWM timer functions of an

8-bit resolution. A counter is incremented using interval timer functions in

synchronization with three types of internal count clocks or the output of 8/16-bit

capture timer/counter. The user can select one of these functions. Therefore, the 8-bit

interval timer can be set and the square wave of any frequency can be output using the

set output. In addition, if a low-pass filter is connected to the PWM output, the D/A

converter can be used.

Interval Timer Functions (Functions to Output the Square Wave)
Interrupts are generated repeatedly at any interval by the interval timer functions.
Because the output level of the pin (P50/PWM pin) can be inverted for each interrupt, the square wave of
any frequency can also be output.
An interval timer operation from the cycle of the count clock to 28-times cycle is possible.
The count clock can be selected from four types.
Table 7.1-1 shows the range of intervals and square wave output.
Table 7.1-1 Range of Intervals and Square Wave Output
Count clock cycle Interval Square wave output (Hz)
1
Internal count
clock
1tINST 1tINST to 28tINST 1/ (2tINST) to 1/ (29tINST)
216tINST 24tINST to 212tINST 1/ (25tINST) to 1/ (213tINST)
364tINST 26tINST to 214tINST 1/ (27tINST) to 1/ (215tINST)
48/16-bit timer
count clock
2tINST 2tINST to 217tINST 1/ (22tINST) to 1/ (210tINST)
32tINST 25tINST to 221tINST 1/ (26tINST) to 1/ (214tINST)
512tINST 29tINST to 225tINST 1/ (210tINST) to 1/ (218tINST)
1tEXT 1tEXT to 216tEXT 1/ (2tEXT) to 1/ (29tEXT)
tINST: Instruction cycle (Affected by the clock mode and others.)
tEXT : Output cycle of an 8/16-bit capture timer