Rev. 1.50
�0
����st ��� �01�
Rev. 1.50
�1
����st ��� �01�
HT66F0175/HT66F0185
A/D Flash MCU with EEPROM
HT66F0175/HT66F0185
A/D Flash MCU with EEPROM
Timer Modules – TM
One of the most fundamental functions in any microcontroller devices is the ability to control and
measure time. To implement time related functions each device includes several Timer Modules,
generally 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
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, Standard and Periodic TM sections.
Introduction
The devices contain two or three TMs depending upon which device is selected with each TM
having a reference name of TM0, TM1, and TM2. Each individual TM can be categorised as a
certain type, namely Compact Type TM, Standard Type TM or Periodic Type TM. Although similar
in nature, the different TM types vary in their feature complexity. The common features to all of the
Compact, Standard and Periodic TMs will be described in this section and the detailed operation
regarding each of the TM types will be described in separate sections. The main features and
differences between the three types of TMs are summarised in the accompanying table.
TM Function
CTM
STM
PTM
Timer/Co�nter
√
√
√
Inp�t Capt�re
—
√
√
Compare Match O�tp�t
√
√
√
PWM Channels
1
1
1
Sin�le P�lse O�tp�t
—
1
1
PWM �li�nment
Ed�e
Ed�e
Ed�e
PWM �dj�stment Period & D�ty
D�ty or Period
D�ty or Period
D�ty or Period
TM Function Summary
Each device in the series contains a specific number of either Compact Type, Standard Type and
Periodic Type TM units which are shown in the table together with their individual reference name,
TM0~TM2.
Device
TM0
TM1
TM2
HT66F01�5
10-bit PTM
10-bit PTM
—
HT66F01�5
16-bit STM
10-bit PTM
16-bit CTM
TM Name/Type Reference
TM Operation
The different types of TM 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 count-up counter whose value is then compared with the value of pre-programmed internal
comparators. When the free running count-up 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.