HT85F2260 Datasheet, PDF (128/226 Pages) Holtek Semiconductor Inc – Standard 8051 8-Bit Flash MCU

Standard 8051 8-Bit Flash MCU
HT85F2260/HT85F2270/HT85F2280
28 ^{Timer/Event Counters 0, 1, 3}
These three timers provide have a similar type and structure and operate with a choice of three
modes for Timers 1 and 3 and four modes for Timer 0. They provide basic timing and event
counting operations.
Introduction
The different operating modes of the timers are selected using the TnM1 and TnM0 bits in the
TMOD or T3CON register.
Timer Mode
0
1
2
3
TnM1, TnM0 bits
00
01
10
11
Mode Name
13-bit Timer-Counter
16-bit Counter
8-bit Counter Auto Reload
Two 8-bit Counters
Application Timer
Timer 0, 1, 3
Timer 0, 1, 3
Timer 0, 1, 3
Timer 0 only
The registers, THn and TLn, are special function registers located in the Special Function Registers
and is the place where the actual timer value is stored. This register pair, are each 8-bit wide, and
can be cascaded into 13-bit or 16-bit wide using mode options. The value in the timer registers
increases by one each time an internal clock pulse is received or an external transition occurs on
the external timer pin. The timer will count from the initial value loaded by the preload register to
their full count at which point the timer overflows and an internal interrupt signal is generated. If
the timer auto-reload mode is selected, the timer value will then be reset with the initial preload
register value and continue counting, otherwise the timer value will be reset to zero. Note that to
achieve a maximum full range count, the preload register must first be cleared to all zeros.
Rev. 1.00
128 of 226
May 15, 2013