Lucent Technologies MN10285K - Manual (Page 120)

Timers
16-Bit Timer Setup Examples
MN102H75K/F75K/85K/F85K LSI User Manual Panasonic Semiconductor Development Company
119
Panasonic
Timer 5 can output a one-shot pulse. Timer 5 does not operate in STOP mode,
when B
OSC
is off. If you use an external clock, it must be synchronized to B
OSC
.
Figure 4-48 shows an example timing diagram for one-shot pulse output. On the
falling edge of TM5IB, the TM5EN flag is set, and counting begins at the start of
the next cycle. Before the count starts, TM5BC is 0, the initial TM5OA output
value is 0, and the R5 (reset) and S5 (set) signals are not asserted. After the count
starts, when it changes from 0 to 1, the S5 signal is asserted. This sets the
TM5OA signal high, and it outputs the one-shot pulse. When the count reaches 3,
TM5BC resets, changing from 3 to 0, and the R5 signal is asserted, causing the
TM5OA signal to go low. Because the TM5ONE bit of the TM5MD register is 1,
and the TM5EN bit is reset, the count stops. The circuit state is now the same as
it was before the TM5IB signal went low. When the TM5IB signal falls again, the
hardware once again sets the TM5EN bit, and the one-shot pulse sequence
repeats.
Figure 4-48 One-Shot Pulse Output Timing (Timer 5)
0000 0003 0002 0001 0000 0003 0002 0001 0000
0003
0001
TM5CA
TM5CB
TM5BC
B OSC /4
TM5EN
TM5IB
S5
R5
TM5OA