THREE-PHASE WAVEFORM MODE
10.2 Block description
When a certain value is written to the dead-time timer register, this value is written to the dead-time reload
register. The M37906 has three dead-time timers, and they are independent each other. When a trigger
is generated due to each of timers A0 through A2, the contents of the dead-time timer reload register are
reloaded; and then, the selected count source is counted down. Simultaneously, the one-shot pulse is
output. A trigger is selected by the dead-time timer trigger select bit (bit 6 at address A616), and the count
source is selected by the clock-source-of-dead-time-timer select bits (bits 7, 6 at address A816). When an
underflow occurs, the counting becomes inactive.
Figure 10.2.5 shows the relationship between the dead-time timer’s pulse and trigger, and Table 10.2.1
lists the pulse width of the dead-time timer.
✕ When dead-time timer trigger select bit = “0”
Timer Ai’s one-shot pulse
Internal
signal
Dead-time timer’s pulse
(Reversed signal)
✕ When dead-time timer trigger select bit = “1”
Timer Ai’s one-shot pulse
Internal
signal
Dead-time timer’s pulse
(Reversed signal)
✕ When re-triggering
Timer Ai’s one-shot pulse
Internal
signal
Re-trigger
Re-trigger
Dead-time timer’s pulse
(Reversed signal)
Fig. 10.2.5 Relationship between dead-time timer’s pulse and trigger
Table 10.2.1 Pulse width of dead-time timer
Trigger
Pulse width
State at trigger input Edge
n : 0016
n : 0116 through FF16
Dead-time timer:
inactive
Rising edge of timer Ai one-shot
1
fi
1
(n+2) ✕
fi
258 ✕
257 ✕
pulse
Falling edge of timer Ai one-shot
pulse
1
fi
1
(n+1) ✕
fi
Dead-time timer:
active
Rising edge of timer Ai one-shot
pulse (Re-trigger)
1
fi
1
(n+1) ✕
fi
257 ✕
Falling edge of timer Ai one-shot
pulse (Re-trigger)
(Note)
(Note)
n: A value which is set in the dead-time timer (address A716
: The dead-time timer’s clock source (f , f /2, f /4)
Note: Width of pulse starting from a re-trigger occurrence timing
)
fi
2
2
2
7906 Group User’s Manual Rev.2.0
10-8
RENESAS [ RENESAS TECHNOLOGY CORP ]
