BS85B12-3 HOLTEK [Holtek Semiconductor Inc], BS85B12-3 Datasheet - Page 69

• 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
Compact Type TM - CTM
Rev. 1.00
BS85B12-3
BS85C20-3
Compact TM Operation
CTM
Although the simplest form of the three TM types, the Compact TM type still contains three operating
modes, which are Compare Match Output, Timer/Event Counter and PWM Output modes. The
Compact TM can also be controlled with an external input pin and can drive one or two external output
pins. These two external output pins can be the same signal or the inverse signal.
At its core is a 10-bit count-up counter which is driven by a user selectable internal or external clock
source. There are also two internal comparators with the names, Comparator A and Comparator P.
These comparators will compare the value in the counter with CCRP and CCRA registers. The CCRP
is three bits wide whose value is compared with the highest three bits in the counter while the CCRA is
the ten bits and therefore compares with all counter bits.
The only way of changing the value of the 10-bit counter using the application program, is to clear the
counter by changing the TnON bit from low to high. The counter will also be cleared automatically by
a counter overflow or a compare match with one of its associated comparators. When these conditions
occur, a TM interrupt signal will also usually be generated. The Compact Type TM can operate in a
number of different operational modes, can be driven by different clock sources including an input pin
and can also control an output pin. All operating setup conditions are selected using relevant internal
registers.
10-bit CTM
10-bit CTM
Name
Compact Type TM Block Diagram
TM No.
0
0
63
TM Input Pin
TCK0
TCK0
TM Output Pin
TP0_0, TP0_1
TP0_0, TP0_1
February 1, 2011