SH7760 Datasheet, PDF (592/1345 Pages) Renesas Technology Corp – SuperHTM RISC engine

16.4.9 Rotary Mode
Each of the two updown-counters can operate in rotary mode. This treats the two input signals as
encoded, as shown in figure 16.11. A rotary switch generates the following waveforms depending
on the direction. The direction is determined by the value of A when a falling edge is detected on
the B input; if A is 1, the direction is left (down is 1) and if A is 0, the direction is right (up is 1).
A is pin 0 and pin 2. B is pin 1 and pin 3. The interrupt edge bit in channels 3 to 0 will be set
whenever a change in the counter value occurs. If a counter overflow or underflow occurs, the
interrupt overflow bit in channels 3 to 0 will be set as well.
A (data)
B (edge)
Right rotation
Left rotation
Figure 16.11 Rotary Mode
16.4.10 Timer Frequency
The frequency of the free running timer and the 16-bit timers can be altered under software control
to be 1 of 4 frequencies. Each 16-bit timer can have an independent clock.
16.4.11 Standby Mode
CMT allows clock gating to reduce power consumption. The module standby mode can be
executed by controlling bit 17 in the Clock Stop Register 00 (CLKSTP00).
To wake up the module, bit 17 in the Clock Stop Clear Register 00 (CLKSTPCLR00) must be
enabled. After enabling this bit all access to CMT can be possible.
To power down the module, the following procedure is required.
1. All channels needs to be in input capture mode (CMTCTL.OP3 - OP0=0000).
2. The active edge for each channel needs to be disabled (CMTCFG.ED3 - ED0=00).
3. Disable bit 17 in the Clock Stop Register 00 (CLKSTP00).
Rev. 1.0, 02/03, page 542 of 1294