MX10E8050X 查看數據表（PDF） - Macronix International
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MX10E8050X Datasheet PDF : 88 Pages
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PRELIMINARY
MX10E8050I /
MX10E8050IA
Timer/Counter
MX10E8050I Serial Timer/Counter 0 and 1 are fully compatible to standard 80C51's.
The MX10E8050I Serial contains two 16-bit Timer/counters, Timer 0 and Timer 1. Timer 0 and Timer 1 may be
programmed to carry out the following functions:
- measure time intervals and pulse durations
- count events
- generate interrupt requests.
Timer 0 and Timer 1
Timers 0 and 1 each have a control bit in TMOD SFR that selects the Timer or counter function of the
corresponding Timer. In the Timer function, the register is incremented every machine cycle. Thus, one can think of
it as counting machine cycles. Since a machine cycle consists of 12 oscillator periods, the count rate is 1/12 of
the oscillator frequency.
In the counter function, the register is incremented in response to a HIGH-to-LOW transition at the corresponding
samples, when the transition shows a HIGH in one cycle and a LOW in the next cycle, the counter is incremented.
Thus, it takes two machine cycles (24 oscillator periods) to recognize a HIGH-to-LOW transition. There are no
restrictions on the duty cycle of the external input signal, but to ensure that a given level is sampled at least once
before it changes, it should be held for at least one full machine cycle.
Timer 0 and Timer 1 can be programmed independently to operate in one of four modes (refer to table 5) :
- Mode 0 : 8-bit Timer/counter with devided-by-32 prescaler
- Mode 1 : 16-bit Timer/counter
- Mode 2 : 8-bit Timer/counter with automatic reload
- Mode 3 : Timer 0 :one 8-bit Timer/counter and one 8-bits Timer. Timer 1 :stopped.
When Timer 0 is in Mode 3, Timer 1 can be programmed to operate in Modes 0, 1 or 2 but cannot set an interrupt
request flag and generate an interrupt. However, the overflow from Timer 1 can be used to pulse the Serial Port
transmission-rgate generator. With a 16 MHz crystal, the counting frequency of these Timer/counters is as follows:
- in the Timer function, the Timer is incremented at a frequency of 1.33 MHz (oscillator frequency divided by 12).
- in the counter function, the frequency handling range for external inputs is 0 Hz to 0.66 MHz (oscillator
frequency divided by 24).
Both internal and external inputs can be gated to the Timer by a second external source for directly measuring
pulse duration.
The Timers are started and stopped under software control. Each one sets its interrupt request flag when it
overflows from all logic 1's to all logic 0's (respectively, the automatic reload value), with the exception of Mode 3
as previously described.
TMOD : TIMER/COUNTER MODE CONTROL REGISTER
This register is located at address 89H.
Table. 4 TMOD SFR (89H)
7
6
5
GATE
C/ T
M1
(MSB)
TIMER 1
4
3
2
1
M0
GATE
C/ T
M1
TIMER 0
0
M0
(LSB)
keep the above table with the following table
P/N:PM0887 Specifications subject to change without notice, contact your sales representatives for the most update information. REV. 1.6, MAR. 28, 2005
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