参数资料
型号: MC68HC705P6ACP
厂商: FREESCALE SEMICONDUCTOR INC
元件分类: 微控制器/微处理器
英文描述: 8-BIT, OTPROM, 2.1 MHz, MICROCONTROLLER, PDIP28
封装: PLASTIC, DIP-28
文件页数: 41/98页
文件大小: 532K
代理商: MC68HC705P6ACP
Capture/Compare Timer
MC68HC705P6A Advance Information Data Sheet, Rev. 2.1
46
Freescale Semiconductor
8.2 Timer Operation
The core of the capture/compare timer is a 16-bit free-running counter. The counter provides the timing
reference for the input capture and output compare functions. The input capture and output compare
functions provide a means to latch the times at which external events occur, to measure input waveforms,
and to generate output waveforms and timing delays. Software can read the value in the 16-bit
free-running counter at any time without affecting the counter sequence.
Because of the 16-bit timer architecture, the I/O registers for the input capture and output compare
functions are pairs of 8-bit registers.
Because the counter is 16 bits long and preceded by a fixed divide-by-4 prescaler, the counter rolls over
every 262,144 internal clock cycles. Timer resolution with a 4-MHz crystal is 2
s.
8.2.1 Input Capture
The input capture function is a means to record the time at which an external event occurs. When the
input capture circuitry detects an active edge on the TCAP pin, it latches the contents of the timer registers
into the input capture registers. The polarity of the active edge is programmable.
Latching values into the input capture registers at successive edges of the same polarity measures the
period of the input signal on the TCAP pin. Latching values into the input capture registers at successive
edges of opposite polarity measures the pulse width of the signal.
8.2.2 Output Compare
The output compare function is a means of generating an output signal when the 16-bit counter reaches
a selected value. Software writes the selected value into the output compare registers. On every fourth
internal clock cycle the output compare circuitry compares the value of the counter to the value written in
the output compare registers. When a match occurs, the timer transfers the programmable output level
bit (OLVL) from the timer control register to the TCMP pin.
The programmer can use the output compare register to measure time periods, to generate timing delays,
or to generate a pulse of specific duration or a pulse train of specific frequency and duty cycle on the
TCMP pin.
8.3 Timer I/O Registers
The following I/O registers control and monitor timer operation:
Timer control register (TCR)
Timer status register (TSR)
Timer registers (TRH and TRL)
Alternate timer registers (ATRH and ATRL)
Input capture registers (ICRH and ICRL)
Output compare registers (OCRH and OCRL)
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相关代理商/技术参数
参数描述
MC68HC705P6ADW 制造商:Rochester Electronics LLC 功能描述:MCU, 176 BYTES RAM, A/D - Bulk
MC68HC705P6AMDW 功能描述:IC MCU 4.6K OTP 2.1MHZ 28-SOIC RoHS:否 类别:集成电路 (IC) >> 嵌入式 - 微控制器, 系列:HC05 标准包装:250 系列:56F8xxx 核心处理器:56800E 芯体尺寸:16-位 速度:60MHz 连通性:CAN,SCI,SPI 外围设备:POR,PWM,温度传感器,WDT 输入/输出数:21 程序存储器容量:40KB(20K x 16) 程序存储器类型:闪存 EEPROM 大小:- RAM 容量:6K x 16 电压 - 电源 (Vcc/Vdd):2.25 V ~ 3.6 V 数据转换器:A/D 6x12b 振荡器型:内部 工作温度:-40°C ~ 125°C 封装/外壳:48-LQFP 包装:托盘 配用:MC56F8323EVME-ND - BOARD EVALUATION MC56F8323
MC68HC705P6AMP 制造商:Rochester Electronics LLC 功能描述:- Bulk
MC68HC705P6CDW 制造商:Motorola Inc 功能描述:
MC68HC705P6CP 制造商:Freescale Semiconductor 功能描述: 制造商:Motorola Inc 功能描述: