mcp3204 ADC芯片输出不稳定

你好，我用的是MCP34和18F45。在我使用18F453与这个ADC芯片之前。效果很好。但是相同的代码不能与18F450一起使用。有一个区别。18F453与外部OSC工作在48 MHz。现在我尝试用8MHz的内部振荡器工作，这个问题是：输出不稳定，振荡范围很宽。有什么想法吗？代码：//**O.N.B.I.T.**********************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************μE//内振荡器KulLAN Youuz VE R6 Pi I／O OLARK KulLAN LabILIL。国际语包括“StA.h”的包括“Saa.h”的“包括”和“ADC”，包括：“LCD16.H”包含“LCD16.H”，包括：EEP。我是你的朋友。包含和lt；pHbb. h & gt；T.H“α”包括：艾伦n de i i i i Keun签署CHAR ADCL；//Adcdn A.Nangde Dyuk k字节n艾伦i de i i Ke//*********原型空隙RAKAM（未签名INTR）；未签名int HARICIAHADC（未签名int CH）；未签名char GonderAlSpi（无符号CHAR数据）；空主（空）{OSCCon＝0xF2；/ /内部振荡器，8MHz CM5ILE 2:0 GRIZ0＝0B10000；//TrISB= 0B000 000 111；/TrISC= 0B000 000 111；Trase= 0B00 000 1111；Delay10ktCyx（160）；A1＝0；A3＝0；B1＝0；B2＝0；B3＝0；/*为（i＝0；I & lt；10；i++）{STR＝32；}*/CSY-ADC= 0；CSYRTC=γ；LCD；LCD；Con＝0x07；TrISD= 0B10000；//PORTD位，3，4，5，CU K（0）；7:In（）；//LCD ILK AyaLaLa yayl L yor Delay10ktCyx（60）；LCDCMD（0x01）；GoOxy（0,0）；打印（“SISSTEM”）；GooTyy（0,1）；打印（“BasLatiLyor…”）打印（“HAZIR”）；GOOTYY（0，1）；打印（“1”）{LCDCMD（0x01）；GOOTYY（0，0）；HARICIAL ADC（0）；RaKAM（SONUC）；Delay10ktCyx（30）；}空隙RAKAM（未签名INTR）{//无符号int t；//无符号INTY；未签名INTS1，S2，S3，S4；S1=（R/1000）；IF（S1=＝0）{打印（“”）；}延迟10ktCyx（200）；GOOTYY（0，0）；= = 0和（S1＝0）{} LCDDATA（S2+48）；}//y= t；S3=（R/10）%10；IF（S1=＝0；和；S2=＝0和；S3＝0）{} LCDDATA（S3+48）；} S4= R% 10；LCDDATA（S4+Y）；}无符号int HARICIAHADC（无符号int CH）{无符号Chan-KaAl；IF（CH＝＝＝＝CH＝＝＝CH＝＝CH＝＝CH＝C=）E{LCDDATA（S1+ 48）；}//y= t；S2=（R/ 100）% 10；IF（S2）{SeaMe＝Kalal= 0x00；//Kaal-Seou-Erki-FiksiyOnOn（CH＝1）{Chanal= 0x40；}否则（CH＝2）{Kaal= 0x80；}否则（CH＝3）{Chanal= 0xC0；} CSYAdC＝0；GonderAlSpi（0x06）；ADC= GordalSPI（KANAL）；ADCL＝GANDALALSPI（0x00）；//子字节0）我在Rasgele Yaz Lm ByByg G OnnDelyDuz。CSYADC＝1；//ADCH和LeNeCK！ADC= ADCH和0x0f；SunuC= ADCH；SunuC= SunuC＆lt；& 8；char GonderAlSpi；（无符号CHAR数据）//SD-I Limleli i在{OpenSPI（SPIOFFSCORY4，MODE00 00，SMPMID）；// BurdA.NCE中MeDeNeCek SangrAdDeNeCek SpEnter de i i iik H.Z.DeEnEnLeli de YaMaLyM.SSPBUF＝数据；SSPSTATBITS；BF）；返回SSPBUF；}



      以下为原文

    Hi,
  I am using mcp3204 with 18f4550. Before I have used 18f4553 with this ADC chip. It worked fine. But the same code is not working with 18f4550. There is one difference. 18f4553 was working with external osc at 48MHz. Now I am trying to work with internal oscillator with 8MHz.
The problem is this: Output is not stable, it oscillate with wide range. Any idea?
the code:
/** C O N F I G U R A T I O N B I T S *******************************/
//#pragma config PLLDIV = 5 // (20 MHz crystal on PICDEM FS USB board)
//#pragma config CPUDIV = OSC1_PLL2
//#pragma config USBDIV = 2 // Clock source from 96MHz PLL/2
//#pragma config FOSC = HSPLL_HS
#pragma config FOSC = INTOSCIO_EC //internal oscillator kullanıyoruz ve RA6 pini I/O olarak kullanılabilir.
#pragma config WDT = OFF, LVP = OFF, MCLRE = OFF// WD yi kapattık yoksa sürekli reset atıyor, LVP kapalı(şimdilik önemsiz bir ayrıntı), MCLRE yi kapattık. yoksa sistemin mcu nun çalışması için mclryi Vdd ye çekmek gerekiyor.
/** I N C L U D E S *************************************************/
#include "p18f4550.h"
#include "delays.h"
#include "saat.h"
#include
#include "timers.h"
#include "lcd16.h"
#include //eeprom ile ilgili kütüphane
#include "config.h"
#include "komut.h"
#include
#include
#include
#include
#include "math.h"
/** V A R I A B L E S ***********************************************/
// değişkenleri buraya yazıyoruz
unsigned int sonuc;
unsigned char adch;//adcden alınan değerin yüksek byteını alan değişken
unsigned char adcl;//adcden alınan değerin düşük byteını alan değişken
//********PROTOTYPES
void rakam(unsigned int r);
unsigned int harici_adc(unsigned int ch);
unsigned char GonderAlSpi(unsigned char data);
void main( void )
{
OSCCON = 0xF2; // internal oscillator, 8MHz
CMCON = 0x07;
TRISD = 0b00000000; // PORTD bit 3,4,5 çıkış (0); 7:5 ile 2:0 giriş (1)
TRISA =0b00000000; //
TRISB =0b00000001;//
TRISC=0b00000111;
TRISE=0x00;
ADCON1 = 0b00001111;
Delay10KTCYx(160);
A1=0;
A2=0;
A3=0;
B1=0;
B2=0;
B3=0;
/*for(i=0;i<10;i++)
{
str=32;
}*/
cs_adc=0;
cs_rtc=1;
lcdinit(); // LCD ilk ayarları yapılıyor
Delay10KTCYx(60);
lcdcmd(0x01);
gotoXy(0,0);
prints("Sistem");
gotoXy(0,1);
prints("Baslatiliyor... ");
Delay10KTCYx(200);
gotoXy(0,0);
prints("hazir ");
gotoXy(0,1);
prints(" ");
while(1)
{
lcdcmd(0x01);
gotoXy(0,0);
harici_adc(0);
rakam(sonuc);
Delay10KTCYx(30);
}

}
void rakam(unsigned int r)
{
//unsigned int t;
//unsigned int y;
unsigned int s1,s2,s3,s4;
s1=(r/1000);
if(s1==0)
{
prints(" ");
}
else
{
lcdData(s1+48);
}
// y=t;
s2=(r/100)%10;
if(s2==0&s1==0)
{
prints(" ");
}
else
{
lcdData(s2+48);
}
//y=t;
s3=(r/10)%10;
if(s1==0&s2==0&s3==0)
{
prints(" ");
}
else
{
lcdData(s3+48);
}
s4=r%10;
lcdData(s4+48);
}
unsigned int harici_adc(unsigned int ch)
{
unsigned char kanal;
if(ch==0)//mpc3204ün kanallarını seçme
{
kanal=0x00;//kanal seçerken fonksiyondan high byte değeri gelmiş oluyor
}
else if(ch==1)
{
kanal=0x40;
}
else if(ch==2)
{
kanal=0x80;
}
else if(ch==3)
{
kanal=0xC0;
}
cs_adc=0;
GonderAlSpi(0x06);
adch=GonderAlSpi(kanal);
adcl=GonderAlSpi(0x00);//son byte ı almak için rastgele yazılmış bir byte gönderiyoruz.
cs_adc=1;//adch and lenecek!
adch=adch&0x0f;
sonuc=adch;
sonuc=sonuc<<8|adcl;
}
unsigned char GonderAlSpi(unsigned char data)//sd işlemleri için
{
OpenSPI(SPI_FOSC_4 ,MODE_00,SMPMID);//burda önce mid denenecek sonra end denenecek SMPEND değişik hız denemeleri de yapmalıyım.
SSPBUF=data;
while(!SSPSTATbits.BF);
return SSPBUF;
}