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Rev. 1.00
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Standard 8051 8-Bit Flash MCU
HT85F2260/HT85F2270/HT85F2280
Timer 2 with
Additional 4-channel PCA
Reload Mode
Module 0 provides a Reload Mode function. In the reload function, preset values in the CRCL and
CRCH registers are loaded into the TL2 and TH2 registers. There are two kinds of Reload modes,
Mode 0 and Mode 1, which are selected by the T2R1 and T2R0 bits in the T2CON register. In
Reload Mode 0, the Reload enable is controlled by the Timer 2 overflow which is an auto reload
and a Timer 2 interrupt will take place. In Reload Mode 1, a falling edge at the T2EX input pin
will reload the data from CRCH/CRCL registers to TH2/TL2 registers. When the external reload
interrupt control bit, EXEN2, and the Timer 2 interrupt control bit, ET2, are both set high, a
Timer 2 interrupt will be generated .The following diagram illustrates the basic operation.
EXEN�
EXF�
Inte���pt
T�ansition
Detecto�
TH�/TL�
Co�nt Enable
CRCH/CRCL
ET�
T�EX
Reload Mode 1
Reload Mode 0
Reload Mode – Module 0