参数资料
型号: ST72C254G1B7
厂商: STMICROELECTRONICS
元件分类: 微控制器/微处理器
英文描述: 8-BIT, FLASH, 6 MHz, MICROCONTROLLER, PDIP32
封装: SHRINK, PLASTIC, DIP-32
文件页数: 76/136页
文件大小: 929K
代理商: ST72C254G1B7
ST72104G, ST72215G, ST72216G, ST72254G
44/136
16-BIT TIMER (Cont’d)
12.2.3.3 Input Capture
In this section, the index,
i, may be 1 or 2 because
there are 2 input capture functions in the 16-bit
timer.
The two input capture 16-bit registers (IC1R and
IC2R) are used to latch the value of the free run-
ning counter after a transition is detected by the
ICAP
i pin (see figure 5).
The IC
iR register is a read-only register.
The active transition is software programmable
through the IEDG
i bit of Control Registers (CRi).
Timing resolution is one count of the free running
counter: (
fCPU/CC[1:0]).
Procedure:
To use the input capture function, select the fol-
lowing in the CR2 register:
– Select the timer clock (CC[1:0]) (see Table 13
Clock Control Bits).
– Select the edge of the active transition on the
ICAP2 pin with the IEDG2 bit (the ICAP2 pin
must be configured as a floating input).
And select the following in the CR1 register:
– Set the ICIE bit to generate an interrupt after an
input capture coming from either the ICAP1 pin
or the ICAP2 pin
– Select the edge of the active transition on the
ICAP1 pin with the IEDG1 bit (the ICAP1pin must
be configured as a floating input).
When an input capture occurs:
– The ICF
i bit is set.
– The IC
iR register contains the value of the free
running counter on the active transition on the
ICAP
i pin (see Figure 31).
– A timer interrupt is generated if the ICIE bit is set
and the I bit is cleared in the CC register. Other-
wise, the interrupt remains pending until both
conditions become true.
Clearing the Input Capture interrupt request (i.e.
clearing the ICF
i bit) is done in two steps:
1. Reading the SR register while the ICF
i bit is set.
2. An access (read or write) to the IC
iLR register.
Notes:
1. After reading the IC
iHR register, the transfer of
input capture data is inhibited and ICF
i will
never be set until the IC
iLR register is also
read.
2. The IC
iR register contains the free running
counter value which corresponds to the most
recent input capture.
3. The 2 input capture functions can be used
together even if the timer also uses the 2 output
compare functions.
4. In One Pulse mode and PWM mode only the
input capture 2 function can be used.
5. The alternate inputs (ICAP1 & ICAP2) are
always directly connected to the timer. So any
transitions on these pins activate the input cap-
ture function.
Moreover if one of the ICAP
i pin is configured
as an input and the second one as an output,
an interrupt can be generated if the user tog-
gles the output pin and if the ICIE bit is set.
This can be avoided if the input capture func-
tion
i is disabled by reading the ICiHR (see note
1).
6. The TOF bit can be used with an interrupt in
order to measure events that exceed the timer
range (FFFFh).
MS Byte
LS Byte
ICiR
IC
iHR
IC
iLR
相关PDF资料
PDF描述
ST72C334J2TC 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PQFP44
ST72314N2TB/XXX 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PQFP64
ST72C314N4TC 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PQFP64
ST72124J2TC/XXX 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PQFP44
ST72334J4TB/XXX 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PQFP44
相关代理商/技术参数
参数描述
ST72C254G1M6 功能描述:8位微控制器 -MCU Flash 4K SPI/I2C RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
ST72C254G2B1 制造商:STMicroelectronics 功能描述:8-BIT MICROCONTROLLER - Bulk
ST72C254G2B6 功能描述:8位微控制器 -MCU Flash 8K SPI/I2C RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
ST72C254G2B6 制造商:STMicroelectronics 功能描述:8BIT MCU FLASH 8K 72C254 DIP32
ST72C254G2M3 功能描述:8位微控制器 -MCU ST72104G ST72215G ST72254G 8B MCU RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT