BS85B12-3 HOLTEK [Holtek Semiconductor Inc], BS85B12-3 Datasheet - Page 107

• 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
Single Pulse Output Mode
To select this mode, the required bit pairs, TnAM1, TnAM0 and TnBM1, TnBM0 should be set to 10
respectively and also the corresponding TnAIO1, TnAIO0 and TnBIO1, TnBIO0 bits should be set to
11 respectively. The Single Pulse Output Mode, as the name suggests, will generate a single shot pulse
on the TM output pin.
The trigger for the pulse TPnA output leading edge is a low to high transition of the TnON bit, which
can be implemented using the application program. The trigger for the pulse TPnB output leading edge
is a compare match from Comparator B, which can be implemented using the application program.
However in the Single Pulse Mode, the TnON bit can also be made to automatically change from low
to high using the external TCKn pin, which will in turn initiate the Single Pulse output of TPnA. When
the TnON bit transitions to a high level, the counter will start running and the pulse leading edge of
TPnA will be generated. The TnON bit should remain high when the pulse is in its active state. The
generated pulse trailing edge of TPnA and TPnB will be generated when the TnON bit is cleared to
zero, which can be implemented using the application program or when a compare match occurs from
Comparator A.
However a compare match from Comparator A will also automatically clear the TnON bit and thus
generate the Single Pulse output trailing edge of TPnA and TPnB. In this way the CCRA value can be
used to control the pulse width of TPnA. The CCRA-CCRB value can be used to control the pulse
width of TPnB. A compare match from Comparator A and Comparator B will also generate TM
interrupts. The counter can only be reset back to zero when the TnON bit changes from low to high
when the counter restarts. In the Single Pulse Mode CCRP is not used. The TnCCLR bit is also not
used.
Single Pulse Generation
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February 1, 2011