參數資料
型號: PIC16C555
廠商: Microchip Technology Inc.
英文描述: OTP 8-Bit CMOS Microcontroller(工作電壓2.5~5.5V,驅動/吸收電流高,微控制器)
中文描述: 檢察官辦公室8位CMOS微控制器(工作電壓2.5?5.5V之間,驅動/吸收電流高,微控制器)
文件頁數: 50/170頁
文件大?。?/td> 4191K
代理商: PIC16C555
PIC16F62X
DS40300C-page 48
Preliminary
2003 Microchip Technology Inc.
7.3
Timer1 Operation in
Asynchronous Counter Mode
If control bit T1SYNC (T1CON<2>) is set, the external
clock input is not synchronized. The timer continues to
increment asynchronous to the internal phase clocks.
The timer will continue to run during SLEEP and can
generate an interrupt on overflow which will wake-up
the processor. However, special precautions in soft-
ware are needed to read/write the timer (Section 7.3.2).
In Asynchronous Counter mode, Timer1 can not be
used as a time-base for capture or compare
operations.
7.3.1
EXTERNAL CLOCK INPUT TIMING
WITH UNSYNCHRONIZED CLOCK
If control bit T1SYNC is set, the timer will increment
completely asynchronously. The input clock must meet
certain minimum high-time and low-time requirements.
Refer to the appropriate Electrical Specifications
section, Timing Parameters 45, 46, and 47.
7.3.2
READING AND WRITING TIMER1 IN
ASYNCHRONOUS COUNTER
MODE
Reading TMR1H or TMR1L while the timer is running,
from an external asynchronous clock, will ensure a
valid read (taken care of in hardware). However, the
user should keep in mind that reading the 16-bit timer
in two 8-bit values itself poses certain problems since
the timer may overflow between the reads.
For writes, it is recommended that the user simply stop
the timer and write the desired values. A write
contention may occur by writing to the timer registers
while the register is incrementing. This may produce an
unpredictable value in the timer register.
Reading the 16-bit value requires some care.
Example 7-1 is an example routine to read the 16-bit
timer value. This is useful if the timer cannot be
stopped.
EXAMPLE 7-1:
READING A 16-BIT FREE-
RUNNING TIMER
; All interrupts are disabled
MOVF TMR1H, W ;Read high byte
MOVWF TMPH ;
MOVF TMR1L, W ;Read low byte
MOVWF TMPL ;
MOVF TMR1H, W ;Read high byte
SUBWF TMPH, W ;Sub 1st read
; with 2nd read
BTFSC STATUS,Z ;Is result = 0
GOTO CONTINUE ;Good 16-bit read
;
; TMR1L may have rolled over between the read
; of the high and low bytes. Reading the high
; and low bytes now will read a good value.
;
MOVF TMR1H, W ;Read high byte
MOVWF TMPH ;
MOVF TMR1L, W ;Read low byte
MOVWF TMPL ;
; Re-enable the Interrupts (if required)
CONTINUE ;Continue with your code
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相關代理商/技術參數
參數描述
PIC16C558/JW 功能描述:8位微控制器 -MCU 3.5KB 128 RAM 13 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數據總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數據 RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT
PIC16C558-04/P 功能描述:8位微控制器 -MCU 3.5KB 128 RAM 13 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數據總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數據 RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT
PIC16C558-04/P 制造商:Microchip Technology Inc 功能描述:IC 8-BIT CMOS MCU
PIC16C558-04/SO 功能描述:8位微控制器 -MCU 3.5KB 128 RAM 13 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數據總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數據 RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT
PIC16C558-04/SS 功能描述:8位微控制器 -MCU 3.5KB 128 RAM 13 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數據總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數據 RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT