TMP91C824
91C824-103
In this mode, a programmable square wave is generated by inverting the timer output each time
the 8-bit up-counter (UC0) matches the value in one of the timer registers TA0REG or TA1REG.
The value set in TA0REG must be smaller than the value set in TA1REG.
Although the up-counter for TMRA1 (UC1) is not used in this mode, TA01RUN<TA1RUN>
should be set to “1”, so that UC1 is set for counting.
Figure 3.7.13 shows a block diagram representing this mode.
Selector
φ
T1
Shift trigger
φ
T4
φ
T16
TA01RUN<TA0RUN>
8-bit
up-counter (UC 0)
Comparator
Comparator
TA0REG
Register Buffer
TA01RUN<TA0RDE>
TA1REG
Internal bus
TA1FF
INTTA0
INTTA1
Inversion
TA01MOD<TA0CLK1:0>
Selector
TA1FFCR<TAFF1IE>
TA0REG-WR
TA1OUT
Figure 3.7.13 Block diagram of 8-Bit PPG Output Mode
If the TA0REG double buffer is enabled in this mode, the value of the register buffer will be
shifted into TA0REG each time TA1REG matches UC0.
Use of the double buffer facilitates the handling of low-duty waves (when duty is varied).
Q
3
Shift from register buffer
Match with TA0REG
and up-Counter
Match with TA1REG
TA0REG
(Value to be compared)
Register buffer
(Up-counter = Q
1
)
Q
1
TA0REG (register buffer)
write
(Up-countner = Q
2
)
Q
2
Q
2
Figure 3.7.14 Operation of register buffer