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参数资料
| 型号： | AT89C51AC2-RLTUM |
| 厂商： | Atmel |
| 文件页数： | 75/121页 |
| 文件大小： | 0K |
| 描述： | IC 8051 MCU FLASH 32K 44VQFP |
| 产品培训模块： | MCU Product Line Introduction |
| 标准包装： | 800 |
| 系列： | 89C |
| 核心处理器： | 8051 |
| 芯体尺寸： | 8-位 |
| 速度： | 40MHz |
| 连通性： | UART/USART |
| 外围设备： | POR，PWM，WDT |
| 输入/输出数： | 34 |
| 程序存储器容量： | 32KB（32K x 8） |
| 程序存储器类型： | 闪存 |
| EEPROM 大小： | 2K x 8 |
| RAM 容量： | 1.25K x 8 |
| 电压 - 电源 (Vcc/Vdd)： | 3 V ~ 5.5 V |
| 数据转换器： | A/D 8x10b |
| 振荡器型： | 外部 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 44-LQFP |
| 包装： | 托盘 |
| 产品目录页面： | 616 (CN2011-ZH PDF) |
| 配用： | AT89OCD-01-ND - USB EMULATOR FOR AT8XC51 MCU |
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57
A/T89C51AC2
4127H–8051–02/08
Timers/Counters
The A/T89C51AC2 implements two general-purpose, 16-bit Timers/Counters. Such are
identified as Timer 0 and Timer 1, and can be independently configured to operate in a
variety of modes as a Timer or an event Counter. When operating as a Timer, the
Timer/Counter runs for a programmed length of time, then issues an interrupt request.
When operating as a Counter, the Timer/Counter counts negative transitions on an
external pin. After a preset number of counts, the Counter issues an interrupt request.
The various operating modes of each Timer/Counter are described in the following
sections.
Timer/Counter
Operations
A basic operation is Timer registers THx and TLx (x = 0, 1) connected in cascade to
form a 16-bit Timer. Setting the run control bit (TRx) in TCON register (see Figure 39)
turns the Timer on by allowing the selected input to increment TLx. When TLx overflows
it increments THx; when THx overflows it sets the Timer overflow flag (TFx) in TCON
register. Setting the TRx does not clear the THx and TLx Timer registers. Timer regis-
ters can be accessed to obtain the current count or to enter preset values. They can be
read at any time but TRx bit must be cleared to preset their values, otherwise the behav-
ior of the Timer/Counter is unpredictable.
The C/Tx# control bit selects Timer operation or Counter operation by selecting the
divided-down peripheral clock or external pin Tx as the source for the counted signal.
TRx bit must be cleared when changing the mode of operation, otherwise the behavior
of the Timer/Counter is unpredictable.
For Timer operation (C/Tx# = 0), the Timer register counts the divided-down peripheral
clock. The Timer register is incremented once every peripheral cycle (6 peripheral clock
periods). The Timer clock rate is FPER/6, i.e. FOSC/12 in standard mode or FOSC/6 in X2
mode.
For Counter operation (C/Tx# = 1), the Timer register counts the negative transitions on
the Tx external input pin. The external input is sampled every peripheral cycles. When
the sample is high in one cycle and low in the next one, the Counter is incremented.
Since it takes 2 cycles (12 peripheral clock periods) to recognize a negative transition,
the maximum count rate is FPER/12, i.e. FOSC/24 in standard mode or FOSC/12 in X2
mode. 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 peripheral cycle.
Timer 0
Timer 0 functions as either a Timer or event Counter in four modes of operation.
Timer 0 is controlled by the four lower bits of TMOD register (see Figure 40) and bits 0,
1, 4 and 5 of TCON register (see Figure 39). TMOD register selects the method of Timer
gating (GATE0), Timer or Counter operation (T/C0#) and mode of operation (M10 and
M00). TCON register provides Timer 0 control functions: overflow flag (TF0), run control
bit (TR0), interrupt flag (IE0) and interrupt type control bit (IT0).
For normal Timer operation (GATE0 = 0), setting TR0 allows TL0 to be incremented by
the selected input. Setting GATE0 and TR0 allows external pin INT0# to control Timer
operation.
Timer 0 overflow (count rolls over from all 1s to all 0s) sets TF0 flag generating an inter-
rupt request.
It is important to stop Timer/Counter before changing mode.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AT89C51AC2SLSUM | 制造商:Adesto Technologies Corporation 功能描述: |
| AT89C51AC2-SLSUM | 功能描述:8位微控制器 -MCU C51AC2 32K FLASHADC EEP 5V 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 |
| AT89C51AC3 | 制造商:ATMEL 制造商全称:ATMEL Corporation 功能描述:Enhanced 8-bit Microcontroller with 64KB Flash Memory |
| AT89C51AC3_04 | 制造商:ATMEL 制造商全称:ATMEL Corporation 功能描述:Microcontrollers |
| AT89C51AC3_05 | 制造商:ATMEL 制造商全称:ATMEL Corporation 功能描述:Enhanced 8-bit Microcontroller with 64KB Flash Memory |
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