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Rev. 1.00
138 of ���
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Standard 8051 8-Bit Flash MCU
HT85F2260/HT85F2270/HT85F2280
Timer 2 with
Additional 4-channel PCA
29
Timer 2 with Additional 4-channel PCA
The structure of Timer 2 is very different from that of Timers 0, 1 and 3 and is therefore described
in its own chapter.
Introduction
The Timer 2 provides the Timer, Event Counter, Gated timer functions and also cooperates with
a 4-channel Programmable Counter Array, known as PCA, to implement the Compare, Reload,
Capture and Programmable Clock Output functions. Each channel has a module, so there are four
modules, named Module 0~Module 3. Each module can be operated as a Compare and Capture
function while Module 0 can also be operated as a Compare, Reload, Capture, known as CRC, and
Programmable Clock Output functions. The accompanying tables and diagram illustrate the PCA
modules functional compare table, timer I/O pin list and basic operational block diagram.
Timer 2 with PCA Modules Operating Modes Summary
Module
Compare
Capture
Reload
Clock Output
0
√
√
√
√
1
√
√
—
—
�
√
√
—
—
3
√
√
—
—
Note:
Mod�le 0 onl� p�ovides the �eload val�e f�om the Time� � capt��e �egiste�s CRCH and CRCL fo�
the Clock O�tp�t Mode. It is impo�tant to note that the act�al Clock O�tp�t pin is T� and not CC0.
Timer 2 with PCA Modules I/O Pins
Function
Input Pins
Output Pins
Compa�e
—
CC0� CC1� CC�� CC3
Reload t�igge�
T�EX
—
Capt��e
CC0� CC1� CC�� CC3
—
Event Co�nte� o� Gated inp�t
T�
—
Clock O�tp�t
—
T�