m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 147

• Manufacturer Part Number: m37905
• Description: Mitsubishi 16-bit Single-chip Microcomputer 7700 Family / 7900 Series
• Manufacturer: Renesas Electronics Corporation.

TIMER A
7.6 Pulse width modulation (PWM) mode
7-44
7.6.3 Operation in PWM mode
The following explains operations of the pulse width modulator.
(1) 16-bit pulse width modulator
(2) 8-bit pulse width modulator
Each time a PWM pulse has been output for one period, the reload register’s contents are reloaded and
When the PWM mode is selected with the operating mode select bits, the TAi
When a trigger is generated, the counter (pulse width modulator) starts counting and the TAi
The timer Ai interrupt request bit is set to “1” each time the PWM pulse level goes from “H” to “L.”
outputs a PWM pulse (Notes 1 and 2).
The interrupt request bit remains set to “1” until the interrupt request is accepted or until the interrupt
request bit is cleared to “0” by software.
the counter continues counting.
When the 16/8-bit PWM mode select bit is cleared to “0,” the counter operates as a 16-bit pulse width
modulator. Figures 7.6.5 and 7.6.6 show operation examples of the 16-bit pulse width modulator.
When the 16/8-bit PWM mode select bit is set to “1,” the counter is divided into 8-bit halves. Then,
the high-order 8 bits operate as an 8-bit pulse width modulator, and the low-order 8 bits operate as
an 8-bit prescaler. Figures 7.6.7 and 7.6.8 show operation examples of the 8-bit pulse width modulator.
Notes 1: If a value “0000
2: When the counter operates as an 8-bit pulse width modulator, after a trigger is generated,
pulse width modulator, the pulse width modulator does not operate and the output from the
TAi
value “00
operates as an 8-bit pulse width modulator, the same is performed.
the TAi
PWM pulse output will start.
OUT
OUT
pin remains “L” level. The timer Ai interrupt request does not occur. Similarly, if a
16
pin outputs “L” level for a period of (1 / f
” is set into the high-order 8 bits of the timer Ai register when the counter
16
” is set into the timer Ai register when the counter operates as a 16-bit
7905 Group User’s Manual Rev.1.0
i
)
(m + 1)
OUT
(n + 1). After that, the
pin outputs “L” level.
OUT
pin