PIC18F46J50来自RA1和RA2的奇数输出

你好。希望有人能帮帮忙吗？为了准备使用18F46J50进行一些开发，有必要使用端口RA0、RA1、RA2和RA3进行纯数字输出。RA0和RA3的作用是预期的，并输出健康的3.3V输出。另一方面，RA1和RA2不守规矩。单独振荡它们会导致1V左右的不良数字输出。如果我将它们一起振荡，那么我得到一个健康的3.3V数字输出。很显然，我做错了什么，并且已经多次读取了数据表。我相信我的模拟设置是正确配置端口的数字，而不是模拟操作。我曾怀疑过比较器，但是想不出还有什么可以改变的。我创建了一个非常简单的程序来振荡端口A引脚（通过不注释该行）来测试各种配置。使用：PIC18F46J50全速USB显示板MPLAB-X 3.51 XC8（V1.38和V1.40）罗德＆施瓦茨HMO2024四通道TopeSchAN你看。



      以下为原文

    Hello. I hope someone can please help?

Getting ready for some development using the 18F46J50, it became necessary to use ports RA0, RA1, RA2 and RA3 for pure digital output. RA0 and RA3 act as expected and output a healthy ~3.3V output. On the other hand, RA1 and RA2 mi***ehave. Oscillating them independently results in a poor digital output of around 1V. If I oscillate them in unison then I get a healthy 3.3V digital output.

Clearly I am doing something wrong and have read the datasheet many times. I believe that my Analogue settings are correctly configuring the ports for digital, rather than analogue operation. I have suspected the Comparator but can't think of anything more that I can change in my configuration that suggests a fix.

I created a very simple program to oscillate Port-A pins (by un-commenting the line) to test various configurations.

Using:
  PIC18F46J50 Full-Speed USB Demonstration Board
  MPLAB-X 3.51
  XC8 (v1.38 and v1.40)
  Rhode & Schwarz HMO2024 4-channel scope

Thank you for looking.
/********************************************************************
* Project: PORTA_Test1
* Module: main.c
* Created: 01Feb17
*******************************************************************/

#include
#include

/********************************************************************
* MAIN - CONFIGURATION
********************************************************************
* Minimal configuration for 8 MHz using internal OSC
*/
#pragma config OSC = INTOSCPLL //Internal OSC with PLL
#pragma config PLLDIV = 2 //Divide by 2 (internal 8MHz input)
#pragma config CPUDIV = OSC1 //No CPU system clock divide

/********************************************************************
* MAIN
*******************************************************************/
void main(void) {

LATEbits.LATE0 = 1;
LATEbits.LATE1 = 1;
TRISEbits.TRISE0 = 1; //LED0
TRISEbits.TRISE1 = 0; //LED1

/****************************************************************
* PORTA
****************************************************************
* RA0/AN0/C1INA/ULPWU/PMA6/RP0 (ICE #42)
* RA1/AN1/C2INA/PMA7/RP1 (ICE #41)
* RA2/AN2/Vref-/CVref/C2INB (ICE #40)
* RA3/AN3/Vref+/C1INB (ICE #39)
*/
#define DEFINE_CONFIGURATOR
#ifdef DEFINE_CONFIGURATOR
CM1CONbits.CON = 0; //Disable comparator #1
CM1CONbits.COE = 0;
CM1CONbits.CREF = 1; //Connect non-inverting output to CVref not C1INA
CM1CONbits.CCH1 = 1; //Connect input to Virv not C1INB
CM1CONbits.CCH0 = 1;
CM2CONbits.CON = 0; //Disable comparator #2
CM2CONbits.COE = 0;
CM2CONbits.CREF = 1; //Connect non-inverting output to CVref
CM2CONbits.CCH1 = 1; //Connect input to Virv not C2INB
CM2CONbits.CCH0 = 1;
#endif

CVRCONbits.CVREN = 0;
CVRCONbits.CVROE = 0;

//AD settings
ADCON0bits.VCFG1 = 0; //Voltage ref uses AVxx not Vref-/AN2
ADCON0bits.VCFG0 = 0; //Voltage ref uses AVDD not Vref+/AN3
ANCON0bits.PCFG0 = 1; //RA0 = digital
ANCON0bits.PCFG1 = 1; //RA1 = digital
ANCON0bits.PCFG2 = 1; //RA2 = digital
ANCON0bits.PCFG3 = 1; //RA3 = digital
LATAbits.LA0 = 0;
LATAbits.LA1 = 0;
LATAbits.LA2 = 0;
LATAbits.LA3 = 0;
TRISAbits.TRISA0 = 0;
TRISAbits.TRISA1 = 0;
TRISAbits.TRISA2 = 0;
TRISAbits.TRISA3 = 0;

/****************************************************************
* MAIN LOOP
****************************************************************
* RA0 produces good 3.3v square wave
* RA1 produces ~500mv output on RA1 and RA2
* RA2 produces ~100mv output on RA1 and RA2
* RA3 produces good 3.3v square wave
*
*/
while(1) {
for(unsigned char i = 0; i < 255; i++);
LATAbits.LA0 = ~LATAbits.LA0; //YEL
// LATAbits.LA1 = ~LATAbits.LA1; //BLU
// LATAbits.LA2 = ~LATAbits.LA2; //VIO
LATAbits.LA3 = ~LATAbits.LA3; //GRN
}
} /* Main */
/* End */

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