SH7046 Datasheet, PDF (456/611 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7046 Series

Section 15 Motor Management Timer (MMT)
Table 15.2 Initial Values of TBRU to TBRW and Initial Output
Initial Value of TBRU to TBRW
TBR = H'0000
H'0000 < TBR ≤ Td
Td < TBR ≤ H'FFFF – 2Td
Initial Output
OLSP = 1, OLSN = 1
OLSP = 0, OLSN = 0
Positive phase: 1
Positive phase: 0
Negative phase: 0
Negative phase: 1
Positive phase: 0
Positive phase: 1
Negative phase: 0
Negative phase: 1
Positive phase: 0
Positive phase: 1
Negative phase: 1
Negative phase: 0
PWM Output Generation in Operating Modes: In the operating modes, a 3-phase PWM
waveform is output with a non-overlap relationship between the positive and negative phases. This
non-overlap time is called the dead time.
The PWM waveform is generated from an output generation waveform generated by ANDing the
compare output waveform with the dead time generation waveform. Waveform generation for one
phase (the U-phase) is shown here. The V-phase and W-phase waveforms are generated in the
same way.
1. Compare Output Waveform
The compare output waveform is generated by comparing the values in the TCNT counter and
the TGR registers.
For compare output waveform U phase A (CMOUA), 0 is output if TGRUU > TCNT in the T1
interval (when TCNT is counting up), and 1 is output if TGRUU ≤ TCNT. In the T2 interval
(when TCNT is counting down), 0 is output if TGRU > TCNT, and 1 is output if TGRU ≤
TCNT.
For compare output waveform U phase B (CMOUB), 1 is output if TGRU > TCNT in the T1
interval, and 0 is output if TGRU ≤ TCNT. In the T2 interval, 1 is output if TGRUD > TCNT,
and 0 is output if TGRUD ≤ TCNT.
2. Dead Time Generation Waveform
For dead time generation waveform U phases A (DTGUA) and B (DTGUB), 1 is output as the
initial value.
TDCNT0 starts counting at the falling edge of CMOUA. DTGUA outputs 0 if TDCNT0 is
counting, and 1 otherwise.
TDCNT1 starts counting at the falling edge of CMOUB. DTGUB outputs 0 if TDCNT1 is
counting, and 1 otherwise.
Rev. 4.00 Dec 05, 2005 page 412 of 564
REJ09B0270-0400