Abstract :TLC0834 is a TI company's eight successive approximation ADC with configurable multi-channel input multiplexer and serial input . Paper to AT89C51 CPU core , using LTC0834 8 serial A / D converter designed to convert an analog signal to digital signal circuits . Keywords :Microcontroller A / D converter TLC0834 SCM control systems typically use the A / D conversion . According to the output signal format , commonly used A / D conversion can be divided into parallel A / D and serial A / D. Generally parallel conversion can be directly received , but the chip 's pin more ; serial approach used in chip pin count, small package , the PCB board space occupied by a small , but require software processing to get the required data . Figure 1 TLC0834 work timing diagram Click to enlarge 1 TLC0834 Introduction The main features of 1.1 TLC0834 TLC0834 is a TI company's 8-bit successive approximation ADC with input ? configurable multi-channel multiplexer and serial input and output forms . The multiplexers can be software configured for single-ended or differential input can also be configured as a pseudo- differential input . In addition, the size of the input reference voltage can be adjusted . 8-bit resolution at all , it allows an arbitrarily small interval of analog voltage coding . TLC0834 is used as serial input structure, so a small package that can save 51 MCU I / O resources, prices are more moderate . Its main features are as follows : ? 8 -bit resolution ; ? Easy and microprocessor interface or independent use; ? can be full -scale work; ? available logic multiplexer address strobe 4 input channels ; ? single 5V power supply , input range is 0 ~ 5V; ? Input and output with TTL, CMOS level compatible ; ? clock frequency of 250kHz , the conversion time is 32µs; ? can National Semiconductor ADC0834 and ADC0838 be replaced , but not along all incorporated within the network of regulators ; ? The total adjusted error of ± 1LSB. 1.2 Characteristics of work TLC0834 and the control processor can be connected to the serial data link to transmit control commands , which ? available software on the input channel selection and configure the control logic table as listed in Table 1 . Input multiplexer configuration can be carried out addressing sequence . Multiplexer addresses can be moved through the DI -side converter . Multiplexer address selects the analog input channel can determine the input is single-ended input or differential input . When the input is differential , the polarity of the input channel should be allocated , and should be assigned to the adjacent differential input on the input channel . For example channel 0 and channel 1 can be selected as a pair of differential input . In addition , the choice of differential input mode, the polarity may choose . A pair of input channels of any one of the two inputs can be used as positive or negative .