ADC0808 IC

13 October 2017 - 0 Comments

ADC0808 IC

ADC0808 Pinout

ADC0808 Pin配置

Pin Number	Pin Name	描述
1 to 5, 27, 28	Analog Channel 1 to 5	这7个引脚是模拟电压（传感器）的输入引脚
6	START	这是一个输入引脚，可以启动转换
7	转换结束（EOC）	This is an output pin which goes high once the conversion is over
8,14,15,18,19,20,21	输出（2^-1到2^-7)	Output digital pins which gives the result of the ADC conversion
9	出去	必须高高地获取输出销的输出
10	CLOCK	Has to be given clock signals (0V-5V) 20Mhz approx.
11	VCC	Powers the IC typically with 5V
12	V Ref（+）	参考电压引脚，通常通常使用 +5V
13	地面	Connect to ground of the circuit
16	vref（ - ）	Vref is connected to ground normally
22	Address Latch Enable(ALE)	该别针应暂时使其选择ADC频道
23,24,25	ADD A, ADD B, ADD C	These three pins are used to select the channel

ADC0808功能

Easy to interface with all Microprocessors or works Stand alone.
八个通道8位ADC模块
可以无缝测量多达8个模拟值
在芯片时钟上不可用，外部Oscillator需要（时钟）
Digital output various from 0 to 255, Operating power is 15mW, conversion time 100us
When Vref = 5V, for every 19.53mV of analog value there will be rise of one bit on digital side (Step size)
Available in 28-pin PDIP, SOIC packages

Note:完整的技术细节可以在ADC0808 datasheet在此页面末尾给出。

ADC0808 Equivalent ICs:

ADC0804, ADC modules

Where to use a ADC0808

TheADC0808 ICis a commonly used ADC module for projects were an external ADC is required. It is a 28-pin Eight channel 8-bit ADC module. Meaning it can measure up to eight ADC value from 0V to 5V and the precision when voltage reference (Vref –pin 9) is +5V is 19.53mV (Step size）。这是在输入侧的每次增长19.53mv的情况下，输出侧将增加1位。

此IC非常适合与微处理器一起使用Raspberry Pi，小猎犬骨骼等，甚至用作独立的ADC模块。每一个ADC模块requires a clock to function; this IC requires an external clock pulse to work. Hence, if you are looking for a ADC module with a decent resolution of 8-bit that could measure up to 8 channels then this IC is for you.

如何使用ADC0808

自从ADC0808 ICcan measure up to eight Analog voltage and also does not have an internal clock slightly requires more components to make it work compared to its predecessor ADC0804. The IC can be powered by +5V. The Vref + and the Output enable should also be supplied +5V to obtained the output. Powering the V ref + with +5V will make the IC operate with a step size of 19.53mV. The external clock should be connected to clock pin, this can either be a oscillator circuit or can just be an pulse generated from a MCU/MPU.

可以将右输入模拟电压从1 in1到In7给出，但是IC一次只能读取一个通道的电压。可以使用引脚添加来完成此频道选择A, ADDBand ADDC。这三个位必须如下表所示设置，以访问相应的模拟通道。设置通道后，应通过使启用地址闩锁（ALE）引脚瞬间启用地址闩锁来启用它。

ADC0808 table

数字输出将从引脚2获得^-1（淘汰1）至2^-8(OUT 8) and the analog voltage should be connected to V in(+) pin as shown in the circuit. Also note that another end of the voltage source (sensor/module) should also be grounded to the circuit for the ADC conversion to work. Now, for the ADC Conversion to start we have o make the START pin to go high as soon as the EOC pin goes high. This can either be done through program or we can simple connect the EOC pin with START pin as shown in the circuit below.

ADC0808 example circuit

In the above circuit I have used a电位计要以0V至5V的可变电压为IN1引脚，并使用电压表读取当前电压。要读取通道ONE的电压，我们必须根据下表设置A = 1和B = 0和C = 0，可以使用MPU/MCU的I/O PIN完成此操作。如您在图像中所见，电压值为2.15V，所得的二进制值为01101110。让我们看看该二进制值如何转换为模拟值，因为我们在编程/设计时需要它。

二进制值=01101110

Converting to Decimal = (0*128)+(1*64）+（1* 32) + (0*16）+（1*8）+（（1*4）+（（1*2)+(0*1）

= 110

Analog Voltage = Decimal Value * Step size

= 110 * 19.53mV

= 2.14V

The obtained value is 2.14V and the measured voltage is 2.15V which are very much close. So this ishow you use an ADC0808 IC。

Applications

Operates With Any 8-Bit (µP) Processors or as a Stand-Alone Device
最多可以测量八个渠道，因此可以用于复杂的项目
Available in smaller packages for its performance, hence used in portable electronics.
广泛用于覆盆子PI，小猎犬骨和其他MPU开发平台
Interface to Temp Sensors, Voltage Sources, and Transducers