S5PV210裸机(九):ADC

news2024/9/25 13:15:26

本文主要探讨210的ADC相关知识。

        ADC
                ADC:模数转换（模拟信号转数字信号）
                量程:模拟电压信号范围(210为0～3.3V)
                精度:若10二进制位来表示精度（210为10位或12位）,量程为0~3.3V,则精度为3.3V/2^10=0.0032265V
                转换速率(MSPS):每秒转多少M数字值,210为 1 MSPS
                通道数:模拟信号输入的路数,210共10ADC通道(AIN[0]~AIN[9]),同时可做10路AD转换,通道引脚为模拟引脚

ADC寄存器

TSADCCON0 ADC的配置

TSDATX0,TSDATY0转出的AD值

CLRINTADC0清中断

ADCMUX选择AD通道

demo：

测试ADC的值变化状况(转动螺丝)

start.S

#define WTCON           0xE2700000
#define SVC_STACK       0xd0037d80
#define SOFT_SW         0xE010E81C
 
.global _start
 
_start:
 
        //set soft switcher,mean set XEINT[0] as PS_HOLD_OUT_EN,set output high level
        ldr r0, =SOFT_SW
        ldr r1, [r0]
        orr r1, r1, #0x300
        orr r1, r1, #0x01
        str r1, [r0]
 
        //close WatchDog
        ldr r0,=WTCON
        ldr r1,=0x0
        str r1,[r0]
 
        //init SVC stack
        ldr sp,=SVC_STACK
 
 
        //init icache
        mrc p15,0,r0,c1,c0,0
        bic r0,r0,#(1<<12)      //close icache
        orr r0,r0,#(1<<12)      //open icache
        mcr p15,0,r0,c1,c0,0 
 
 
        //use func
        bl main
 
        b .

main.c

#include "uart_printf.h"
#include "adc.h"
#include "stdio.h"

int main()
{
        //init uart
        init_uart();
        printf("init uart\r\n");

        //init adc
        printf("init adc\r\n");
        init_adc();

        //read adc
        printf("read adc data\r\n");
        read_adc_data();

        return 0;
}

uart_printf.h

void init_uart();

uart_printf.c

#define GPA0CON         0xE0200000
 
#define ULCON0          0xE2900000
#define UCON0           0xE2900004
#define UFCON0          0xE2900008
#define UMCON0          0xE290000C
#define UTRSTAT0        0xE2900010
#define UTXH0           0xE2900020
#define URXH0           0xE2900024
#define UBRDIV0         0xE2900028
#define UDIVSLOT0       0xE290002C
 
#define rGPA0CON        (*(volatile unsigned int *)GPA0CON)
#define rULCON0         (*(volatile unsigned int *)ULCON0)
#define rUCON0          (*(volatile unsigned int *)UCON0)
#define rUFCON0         (*(volatile unsigned int *)UFCON0)
#define rUMCON0         (*(volatile unsigned int *)UMCON0)
#define rUTRSTAT0       (*(volatile unsigned int *)UTRSTAT0)
#define rUTXH0          (*(volatile unsigned int *)UTXH0)
#define rURXH0          (*(volatile unsigned int *)URXH0)
#define rUBRDIV0        (*(volatile unsigned int *)UBRDIV0)
#define rUDIVSLOT0      (*(volatile unsigned int *)UDIVSLOT0)
 
//init uart
void init_uart()
{
        //set gpio as uart(rx,tx)
        rGPA0CON &= ~(0xff);
        rGPA0CON |= ((1<<2)|(1<<5));
 
        //set uart base configure(mode)
        rULCON0 = 0x3;
        rUCON0 = 0x5;
        rUMCON0 = 0;
        rUFCON0 = 0;
 
        //set uart baud
        //DIV_VAL = (PCLK / (bps x 16))-1
        //(66000000 /(115200 * 16)) -1 = 34.8
        rUBRDIV0 = 34;
 
        //set uart baud calibration
        //0.8 * 16 = 13,check 210 table
        rUDIVSLOT0 = 0xdfdd;
}
 
 
//send data
void putc(char data)
{                  
        while (!(rUTRSTAT0 & (1<<1)));
        rUTXH0 = data;
}
 
//receive data
char getc()
{
        while (!(rUTRSTAT0 & (1<<0)));
        return (rURXH0 & 0xff);
}

adc.h

void init_adc();

void read_adc_data();

adc.c

#include "stdio.h"

#define TSADCCON0       0xE1700000
#define TSDATX0         0xE170000C
#define TSDATY0         0xE1700010
#define ADCMUX          0xE170001C

#define rTSADCCON0      (*(volatile unsigned int *)TSADCCON0)
#define rTSDATX0        (*(volatile unsigned int *)TSDATX0)
#define rTSDATY0        (*(volatile unsigned int *)TSDATY0)
#define rADCMUX         (*(volatile unsigned int *)ADCMUX)

static void dealy_time()
{
        volatile unsigned int num = 900000;
        while(num--);
}

void init_adc()
{
        //set adc is 10 bit 
        rTSADCCON0 |= (1<<16); 
        //set adc enable prescaler 
        rTSADCCON0 |= (1<<14);
        //set adc prescaler value,value = 66 / (65 + 1) = 1Mhz
        rTSADCCON0 &= ~(0xff<<6);
        rTSADCCON0 |= (65<<6); 
        //set adc mode(normal)
        rTSADCCON0 &= ~(1<<2);
        //close when start adc is read only
        rTSADCCON0 &= ~(1<<1);
        //select adc channel 0
        rADCMUX &= ~(0xf);
}

void read_adc_data()
{
        volatile unsigned int x_value = 0;
        volatile unsigned int y_value = 0;
        while(1)
        {
                //start adc
                rTSADCCON0 |= (1<<0);
                //judge adc adc covert status(end or ing)
                while(!(rTSADCCON0 & (1<<15)));
                //read adc data
                x_value = rTSDATX0;
                y_value = rTSDATY0;
                printf("read adc data :   x : %d    y : %d\r\n",(x_value & 0xfff),(y_value & 0xfff));
                dealy_time();
        }
}

link.lds

SECTIONS
{
        . = 0xd0020010;
 
        .text : 
        {
                start.o
                * (.text)
        }
    
        .data : 
        {
                * (.data)
        }
 
        bss_start = .;
 
        .bss : 
        {
                * (.bss)
        }
}

Makefile

CC      =       arm-linux-gcc
LD      =       arm-linux-ld
OBJCOPY =       arm-linux-objcopy
OBJDUMP =       arm-linux-objdump
 
INCDIR  := $(shell pwd)
 
#预处理器的flag，flag就是编译器可选的选项
CPPFLAGS  := -nostdlib -nostdinc -I$(INCDIR)/include
#C编译器的flag
CFLAGS    := -Wall -O2 -fno-builtin
 
export CC LD OBJCOPY OBJDUMP CPPFLAGS CFLAGS
 
objs      := start.o uart_printf.o main.o adc.o
objs      += lib/libc.a
 
led.bin:$(objs)
        $(LD) -Tlink.lds -o adc.elf $^
        $(OBJCOPY) -O binary adc.elf adc.bin
        $(OBJDUMP) -D adc.elf > adc.dis
        gcc mkv210.c -o mkv210
        ./mkv210 adc.bin sd.bin
 
lib/libc.a:
        cd lib;  make;  cd ..
 
%.o:%.S
        $(CC) $(CPPFLAGS) $(CFLAGS) -o $@ $< -c
 
%.o:%.c
        $(CC) $(CPPFLAGS) $(CFLAGS) -o $@ $< -c
 
clean:
        rm *.o *.elf *.bin *.dis mkv210 -f
        cd lib; make clean; cd ..

文件示例：