12/15/2023 0 Comments Microprocessor 8085 timing diagramSummary − So this instruction ANA E requires 2-Bytes, 2 Machine Cycles (Opcode Fetch, Memory Read) and 7 T-States for execution as shown in the timing diagram. The timing diagram against this instruction ANI CDH execution is as follows. The internal calculation has been done as follows − The result of execution of this instruction has been depicted in the following tracing table − So after this ANI operation result will be stored back on to the Accumulator itself. Timing and state diagram and Memory interfacing of 8085 Microprocessor Md Mahbubur Rahman Haldar The address bus has 8 signal lines A8 -A15 which are unidirectional. We are considering the initial content of Accumulator is ABH. Let us consider ANI CDH as a sample instruction of this type. As it is an arithmetic operation do S, P, and Z flags are affected based on the result. The result of this ANDingoperation will be stored in the Accumulator itself over writing its previous content. This instruction is used to AND 8-bit immediate data with the Accumulator’s content. We are using IN0 as input pin, so the pin selection value will be 00H.In 8085 Instruction set, ANI is a mnemonic, which stands for “ANd Immediate with Accumulator” and “d8” stands for any 8-bit or 1-Bytedata. So input operands will reside on Accumulator and R registers and after addition the result will be stored back on to Accumulator. As addition is a binary operation, so it requires two operands to be operated on. Now let us see a program to generate digital signal from analog data. In 8085 Instruction set, ADD R is a mnemonic that stands for Add contents of R to Accumulator. The PC 3 pin is connected to the Start of Conversion (SOC) pin and ALE pin of ADC 0808/0809. The PC 2-0 lines are connected to three address pins of this chip to select input channels. The PC 7 pin of Port C upper is connected to the End of Conversion (EOC) Pin of the analog to digital converter. The PortA of 8255 chip is used as the input port. Let us see the circuit diagram of connecting 8085, 8255 and the ADC converter. To interface the ADC with 8085, we need 8255 Programmable Peripheral Interface chip with it. The functional block diagram of this chip is like this Let us see some good features of ADC 0808/0809Įxcellent long term accuracy and repeatability One of the main advantage of this chip is that it does not require any external zero and full scale adjustment, only +5V DC supply is sufficient. This device uses successive approximation technique to convert analog signal to digital form. ADC 0808/0809 is a monolithic CMOS device. This chip is popular and widely used ADC. It has 8 channel multiplexer to interface with the microprocessor. The ADC 0808/0809 is an 8-bit analog to digital converter. As the first process uses flash type, so it is expensive and difficult to design for high accuracy. The first process is faster but less accurate, the second one is more accurate. This process includes integrator-converters and voltage-to-frequency converters. In another technique it determines the changing of analog signals into time or frequency. In this technique, it includes successive approximation, counter and flash type converters. In the first technique it compares given analog signal with the initially generated equivalent signal. The A/D converters can be classified into two groups based on their conversion techniques. Here the analog signal is represented by equivalent binary states. The Analog to Digital Conversion is a quantizing process. In this section we will see how ADC (Analog to Digital Converter) works with Intel 8085 Microprocessor.
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