BS85B12-3 HOLTEK [Holtek Semiconductor Inc], BS85B12-3 Datasheet - Page 84

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

Note:
Rev. 1.00
TM O/P Pin
Flag TnAF
Flag TnPF
CCRA Int.
CCRP Int.
TnPAU
TnPOL
0x3FF
CCRA
CCRP
TnON
Counter Value
1. With TnCCLR=1 a Comparator A match will clear the counter
2. The TM output pin is controlled only by the TnAF flag
3. The output pin is reset to its initial state by a TnON bit rising edge
4. A TnPF flag is not generated when TnCCLR=1
Timer/Counter Mode
Output pin set to
initial Level Low
if TnOC=0
As the name of the mode suggests, after a comparison is made, the TM output pin, will change state.
The TM output pin condition however only changes state when a TnAF interrupt request flag is
generated after a compare match occurs from Comparator A. The TnPF interrupt request flag,
generated from a compare match occurs from Comparator P, will have no effect on the TM output pin.
The way in which the TM output pin changes state are determined by the condition of the TnIO1 and
TnIO0 bits in the TMnC1 register. The TM output pin can be selected using the TnIO1 and TnIO0 bits
to go high, to go low or to toggle from its present condition when a compare match occurs from
Comparator A. The initial condition of the TM output pin, which is setup after the TnON bit changes
from low to high, is setup using the TnOC bit. Note that if the TnIO1 and TnIO0 bits are zero then no
pin change will take place.
To select this mode, bits TnM1 and TnM0 in the TMnC1 register should be set to 11 respectively. The
Timer/Counter Mode operates in an identical way to the Compare Match Output Mode generating the
same interrupt flags. The exception is that in the Timer/Counter Mode the TM output pin is not used.
Therefore the above description and Timing Diagrams for the Compare Match Output Mode can be
used to understand its function. As the TM output pin is not used in this mode, the pin can be used as a
normal I/O pin or other pin-shared function.
TnPF not
generated
Here TnIO [1:0] = 11
Toggle Output select
CCRA > 0 Counter cleared by CCRA value
Touch Key Flash MCU with LCD/LED Driver
Output Toggle with
TnAF flag
Compare Match Output Mode -- TnCCLR = 1
Note TnIO [1:0] = 10
Active High Output select
78
Pause
Output not affected by
TnAF flag. Remains High
until reset by TnON bit
Resume
TnCCLR = 1; TnM [1:0] = 00
BS85B12-3/BS85C20-3
Stop
Output controlled by
other pin-shared function
CCRA=0
Counter Restart
Output Pin
Reset to Initial value
CCRA = 0
Counter overflow
Output Inverts
when TnPOL is high
February 1, 2011
No TnAF flag
generated on
CCRA overflow
Output does
not change
Time