Rev. 1.20
68
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Rev. 1.20
69
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BS82B12A-3/BS82C16A-3/BS82D20A-3
Touch Key 8-Bit Flash MCU with LED/LCD Driver
BS82B12A-3/BS82C16A-3/BS82D20A-3
Touch Key 8-Bit Flash MCU with LED/LCD Driver
Timer Modules – TM
One of the most fundamental functions in any microcontroller device is the ability to control and
measure time. To implement time related functions the device includes several Timer Modules,
abbreviated to the name TM. The TMs are multi-purpose timing units and serve to provide
operations such as Timer/Counter, Input Capture, Compare Match Output and Single Pulse Output
as well as being the functional unit for the generation of PWM signals. Each of the TMs has two
individual interrupts. The addition of input and output pins for each TM ensures that users are
provided with timing units with a wide and flexible range of features.
The common features of the different TM types are described here with more detailed information
provided in the individual Compact and Periodic TM sections
.
Introduction
Each device contains a 10-bit Compact TM, CTM, and a 10-bit Periodic TM, PTM. Although
similar in nature, the different TM types vary in their feature complexity. The common features to
the Compact and Periodic TMs will be described in this section and the detailed operation will be
described in corresponding sections. The main features and differences between the two types of
TMs are summarised in the accompanying table.
Function
CTM
PTM
Time�/Co�nte�
√
√
I/P Capt��e
—
√
Compa�e Match O�tp�t
√
√
PWM Channels
1
1
Single P�lse O�tp�t
—
1
PWM Alignment
Edge
Edge
PWM Adj�stment Pe�iod & D�t�
D�t� o� Pe�iod
D�t� o� Pe�iod
TM Function Summary
CTM0
PTM0
10-bit CTM
10-bit PTM
TM Name/Type Reference
TM Operation
The two different types of TMs offer a diverse range of functions, from simple timing operations
to PWM signal generation. The key to understanding how the TM operates is to see it in terms of
a free running counter whose value is then compared with the value of pre-programmed internal
comparators. When the free running counter has the same value as the pre-programmed comparator,
known as a compare match situation, a TM interrupt signal will be generated which can clear the
counter and perhaps also change the condition of the TM output pin. The internal TM counter is
driven by a user selectable clock source, which can be an internal clock or an external pin.
TM Clock Source
The clock source which drives the main counter in each TM can originate from various sources. The
selection of the required clock source is implemented using the
xTn
CK2~
xTn
CK0 bits in the
xTMn
control registers, where
"x"
can stand for C or P and
"n"
is the serial number. The clock source can
be a ratio of either the system clock f
SYS
or the internal high clock f
H
, the f
SUB
clock source or the
external TCK
n
pin. The TCK
n
pin clock source is used to allow an external signal to drive the TM
as an external clock source or for event counting.
Содержание BS82B12A-3
Страница 33: ...Rev 1 20 33 January 23 2015 BS82B12A 3 BS82C16A 3 BS82D20A 3 Touch Key 8 Bit Flash MCU with LED LCD Driver ...
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