BS85B12-3 HOLTEK [Holtek Semiconductor Inc], BS85B12-3 Datasheet - Page 93

• Manufacturer Part Number: BS85B12-3
• Description: Touch Key Flash Type 8-Bit MCU with LCD/LED Driver
• Manufacturer: HOLTEK [Holtek Semiconductor Inc]

BS85B12-3/BS85C20-3
Touch Key Flash MCU with LCD/LED Driver
Rev. 1.00
Bit 3
Bit 2
Bit 1
Bit 0
Timer/counter Mode
These two bits are used to determine how the TM output pin changes state when a certain
condition is reached. The function that these bits select depends upon in which mode the TM is
running.
In the Compare Match Output Mode, the T1AIO1 and T1AIO0 bits determine how the TM
output pin changes state when a compare match occurs from the Comparator A. The TM output
pin can be setup to switch high, switch low or to toggle its present state when a compare match
occurs from the Comparator A. When the bits are both zero, then no change will take place on
the output. The initial value of the TM output pin should be setup using the T1AOC bit in the
TM1C1 register. Note that the output level requested by the T1AIO1 and T1AIO0 bits must be
different from the initial value setup using the T1AOC bit otherwise no change will occur on the
TM output pin when a compare match occurs. After the TM output pin changes state it can be
reset to its initial level by changing the level of the T1ON bit from low to high.
In the PWM Mode, the T1AIO1 and T1AIO0 bits determine how the TM output pin changes state
when a certain compare match condition occurs. The PWM output function is modified by
changing these two bits. It is necessary to change the values of the T1AIO1 and T1AIO0 bits
only after the TM has been switched off. Unpredictable PWM outputs will occur if the T1AIO1
and T1AIO0 bits are changed when the TM is running
T1AOC: TP1A Output control bit
Compare Match Output Mode
This is the output control bit for the TM output pin. Its operation depends upon whether TM is
being used in the Compare Match Output Mode or in the PWM Mode/ Single Pulse Output Mode.
It has no effect if the TM is in the Timer/Counter Mode. In the Compare Match Output Mode it
determines the logic level of the TM output pin before a compare match occurs. In the PWM
Mode it determines if the PWM signal is active high or active low.
T1APOL: TP1A Output polarity Control
This bit controls the polarity of the TP1A output pin. When the bit is set high the TM output pin
will be inverted and not inverted when the bit is zero. It has no effect if the TM is in the
Timer/Counter Mode.
T1CDN: TM1 Counter count up or down flag
T1CCLR: Select TM1 Counter clear condition
This bit is used to select the method which clears the counter. Remember that the Enhanced
TM contains three comparators, Comparator A, Comparator B and Comparator P, but only
Comparator A or Comparator Pan be selected to clear the internal counter. With the T1CCLR bit
set high, the counter will be cleared when a compare match occurs from the Comparator A.
When the bit is low, the counter will be cleared when a compare match occurs from the
Comparator P or with a counter overflow. A counter overflow clearing method can only be
implemented if the CCRP bits are all cleared to zero. The T1CCLR bit is not used in the PWM,
Single Pulse or Input Capture Mode.
Mode/ Single Pulse Output Mode
Unused
0: Initial low
1: Initial high
0: Active low
1: Active high
0: Non-invert
1: Invert
0: Count up
1: Count down
0: TM1 Comparator P match
1: TM1 Comparator A match
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February 1, 2011