SH7144 Datasheet, PDF (323/773 Pages) Renesas Technology Corp – Hitachi SuperH RISC engine

A/D Conversion Start Request Setting: In complementary PWM mode, an A/D conversion start
request can be issued using a TGRA_3 compare-match or a compare-match on a channel other
than channels 3 and 4.
When start requests using a TGRA_3 compare-match are set, A/D conversion can be started at the
center of the PWM pulse.
A/D conversion start requests can be set by setting the TTGE bit to 1 in the timer interrupt enable
register (TIER).
Complementary PWM Mode Output Protection Function
Complementary PWM mode output has the following protection functions.
• Register and counter miswrite prevention function
With the exception of the buffer registers, which can be rewritten at any time, access by the CPU
can be enabled or disabled for the mode registers, control registers, compare registers, and
counters used in complementary PWM mode by means of the MTURWE bit in the bus
controller’s bus control register 1 (BCR1). The applicable registers are some (21 in total) of the
registers in channels 3 and 4 shown in the following:
TCR_3 and TCR_4, TMDR_3 and TMDR_4, TIORH_3 and TIORH_4, TIORL_3 and
TIORL_4, TIER_3 and TIER_4, TCNT_3 and TCNT_4, TGRA_3 and TGRA_4, TGRB_3
and TGRB_4, TOER, TOCR, TGCR, TCDR, and TDDR.
This function enables miswriting due to CPU runaway to be prevented by disabling CPU access to
the mode registers, control registers, and counters. When the applicable registers are read in the
access-disabled state, undefined values are returned. Writing to these registers is ignored.
• Halting of PWM output by external signal
The 6-phase PWM output pins can be set automatically to the high-impedance state by
inputting specified external signals. There are four external signal input pins.
See section 11.9, Port Output Enable (POE), for details.
• Halting of PWM output when oscillator is stopped
If it is detected that the clock input to this LSI has stopped, the 6-phase PWM output pins
automatically go to the high-impedance state. The pin states are not guaranteed when the clock
is restarted.
See section 4.2, Function for Detecting the Oscillator Halt.
Rev. 2.0, 09/02, page 283 of 732