参数资料
| 型号： | AT90LS2343-1SI |
| 厂商： | Atmel |
| 文件页数： | 35/63页 |
| 文件大小： | 0K |
| 描述： | IC MCU 2K FLASH 1MHZ IND 8-SOIC |
| 标准包装： | 95 |
| 系列： | AVR® 90LS |
| 核心处理器： | AVR |
| 芯体尺寸： | 8-位 |
| 速度： | 1MHz |
| 连通性： | SPI |
| 外围设备： | 欠压检测/复位，POR，WDT |
| 输入/输出数： | 5 |
| 程序存储器容量： | 2KB（1K x 16） |
| 程序存储器类型： | 闪存 |
| EEPROM 大小： | 128 x 8 |
| RAM 容量： | 128 x 8 |
| 电压 - 电源 (Vcc/Vdd)： | 2.7 V ~ 6 V |
| 振荡器型： | 内部 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 8-SOIC（0.209"，5.30mm 宽） |
| 包装： | 管件 |
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2002 Microchip Technology Inc.
Preliminary
DS41139B-page 39
PIC16C433
7.2
Using Timer0 with an External Clock
When an external clock input is used for Timer0, it must
meet certain requirements. The requirements ensure
the external clock can be synchronized with the internal
phase clock (TOSC). Also, there is a delay in the actual
incrementing of Timer0 after synchronization.
7.2.1
EXTERNAL CLOCK SYNCHRONIZATION
When no prescaler is used, the external clock input is
used as the clock source. The synchronization of
T0CKI with the internal phase clocks is accomplished
by sampling the prescaler output on the Q2 and Q4
cycles of the internal phase clocks (Figure 7-5). There-
fore, it is necessary for T0CKI to be high for at least
2TOSC (and a small RC delay of 20 ns) and low for at
least 2TOSC (and a small RC delay of 20 ns). Refer to
the electrical specification of the desired device.
When a prescaler is used, the external clock input is
divided by the asynchronous ripple-counter type pres-
caler, so that the prescaler output is symmetrical. For
the external clock to meet the sampling requirement,
the ripple-counter must be taken into account. There-
fore, it is necessary for T0CKI to have a period of at
least 4TOSC (and a small RC delay of 40 ns), divided by
the prescaler value. The only requirement on T0CKI
high and low time is that they do not violate the mini-
mum pulse width requirement of 10 ns. Refer to param-
eters 40, 41 and 42 in the electrical specification of the
desired device.
7.2.2
TMR0 INCREMENT DELAY
Since the prescaler output is synchronized with the
internal clocks, there is a small delay from the time the
external clock edge occurs to the time the Timer0 mod-
ule is actually incremented. Figure 7-5 shows the delay
from the external clock edge to the timer incrementing.
FIGURE 7-5:
TIMER0 TIMING WITH EXTERNAL CLOCK
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
External Clock Input or
Prescaler Output(2)
External Clock/Prescaler
Output after Sampling
Increment Timer0 (Q4)
Timer0
T0
T0 + 1
T0 + 2
Small pulse
misses sampling
(3)
(1)
Note 1:
Delay from clock input change to Timer0 increment is 3T
OSC to 7TOSC (Duration of Q = TOSC). Therefore, the error in measuring
the interval between two edges on Timer0 input = ±4T
OSC max.
2:
External clock if no prescaler selected; prescaler output otherwise.
3:
The arrows indicate the points in time where sampling occurs.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AT90LS2343-4PC | 功能描述:8位微控制器 -MCU 2k bit 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 |
| AT90LS2343-4PI | 功能描述:8位微控制器 -MCU 2k bit 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 |
| AT90LS2343-4SC | 制造商:ATMEL 制造商全称:ATMEL Corporation 功能描述:8-Bit Microcontroller with 2K Bytes of In-System Programmable Flash |
| AT90LS2343-4SI | 功能描述:8位微控制器 -MCU 2k bit 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 |
| AT90LS2343-4SI SL383 | 制造商:Atmel Corporation 功能描述:4MHZSOICIND TEMP3.0V |
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