ADC (Analog to Digital conversion) using LPC 1768
0 likes553 views
This document contains code for an interfacing diagram that converts analog to digital values and displays the output in hexadecimal on an LCD screen. The code configures the ADC and UART ports, performs an analog to digital conversion on an input voltage, converts the output to hexadecimal, and transmits the values over UART. It also contains calculations for the step size of the ADC based on the reference voltage and bits. An observation table shows theoretical and measured output values for different input voltages.
ADC (Analog to Digital conversion) using LPC 1768
- 1. Interfacing diagram: Code: #include<stdio.h> #include "LPC1768_Includes.h" void hextoASCII(int myValue); int main() { unsigned int rx; PINSEL3 = 0xC0000000; // configure port 1 for ADC input p1.31 PCONP = 1 << 12; // A/D converter (ADC) power/clock control bit. AD0CR = 0x01200220; // A/D Control Register, SEL, CLKDIV, BURST bit AD0GDR = 0x05000000; // A/D Global Data Register
- 2. while((AD0GDR & 0x80000000)!=0x80000000); //check done bit conversion rx=(AD0GDR & 0x0000FFF0); rx = rx >>4; hextoASCII(rx); } void hextoASCII(int myValue) //hex to ascii conversion { unsigned int i, d1, d2,d3,d4; d1 = myValue% 0x0A; d1 = d1 | 0x30; d2 = (myValue/0x0A) % 0x0A; d2 = d2 | 0x30; d3 = (myValue/0x0A/0x0A)% 0x0A; d3 = d3 | 0x30; d4 = (myValue/0x0A/0x0A/0x0A)% 0x0A; d4 = d4 | 0x30; //UART0 configuration PINSEL0=0x00000050; PCONP=0x08; U0FCR = 0x07;
- 3. U0LCR = 0x83; U0DLL = 0x75; U0DLM = 0x00; U0LCR = 0x03; U0TER = 0x80; while(1) { //transmitting bit by bit while(!(U0LSR & 0x20)); U0THR=d4; for(i=0;i<255;i++); while(!(U0LSR & 0x20)); U0THR=d3; for(i=0;i<255;i++); while(!(U0LSR & 0x20)); U0THR=d2; for(i=0;i<255;i++); while(!(U0LSR & 0x20)); U0THR=d1; for(i=0;i<255;i++); while(!(U0LSR & 0x20)); U0THR=' '; for(i=0;i<255;i++); } }
- 4. Calculations: Step size= 𝑉𝑟𝑒𝑓 2 𝑛 = 3.3 212= 8.056641 x 10−4 Vout= 𝑉𝑖𝑛 𝑆𝑡𝑒𝑝 𝑠𝑖𝑧𝑒 Observation Table: Vin (volts) Vout (Therotical) Vout (hex) Vout (decimal) 1 1241.212 0x04D9 1241 1.5 1861.818 0x0745 1861 2 2482.590 0x09B2 2482 2.5 3103.042 0x0C1F 3103 3 3723.636 0x0E8B 3723 3.3 4095.999 0x0FFF 4095 Output: 1V
- 5. 1.5 V 2V
- 6. 2.5 V 3V
- 7. 3.3V