[討論] PIC32MX440F256H

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電梯直達

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發表於 2023-4-26 18:56:19 |只看該作者 |倒序瀏覽

製作多通道示波器的零件清單：

PIC32MX440F256H 微控制器
128x64 黑白 OLED 顯示屏
AD9286-80 8 位 80 MSPS ADC
多路放大器
訊號開關
快速二極體
多路電位器
轉換器
滑動式電位器
電晶體

以下是 PIC32MX440F256H 微控制器腳位圖：

   +----------------------------------------+
   |       PIC32MX440F256H 腳位圖          |
   +----------------------------------------+
            _______ _______
            |    \/    |
         MCLR |1          64| VDD
      ICSPDAT |2          63| VSS
      ICSPCLK |3          62| PGED1
         RB0 |4          61| PGEC1
         RB1 |5          60| AN15/RB15
         RB2 |6          59| AN14/RB14
         RB3 |7          58| AN13/RB13
         RB4 |8          57| AN12/RB12
         RB5 |9          56| AN11/RB11
         RB6 |10          55| AN10/RB10
         RB7 |11          54| AN9/RB9
         RB8 |12          53| AN8/RB8
         RB9 |13          52| AN7/RB7
         RB10 |14          51| AN6/RB6
         RB11 |15          50| AN5/RB5
         RB12 |16          49| AN4/RB4
         RB13 |17          48| AN3/RB3
         RB14 |18          47| AN2/RB2
         RB15 |19          46| AN1/RB1
      VUSB3V3 |20          45| AN0/RB0
      VBUSON |21          44| AVDD
         VDD |22          43| AVSS
         VSS1 |23          42| RE5
         RA0 |24          41| RE4
         RA1 |25          40| RE3
         RA2 |26          39| RE2
         RA3 |27          38| RE1
         RA4 |28          37| RE0
         RA5 |29          36| VCAP
         VSS2 |30          35| VSS
         RD0 |31          34| RD7
         RD1 |32          33| RD6
            +---------------+
程式碼：

以下是 PIC32MX440F256H 微控制器的多通道示波器的程式碼
用於顯示 ADC 讀數的圖形：

#include <p32xxxx.h>
#include <plib.h>
#include <stdio.h>

#pragma config FNOSC = FRCPLL
#pragma config FPLLIDIV
#pragma config FPLLMUL = MUL_20
#pragma config FPLLODIV = DIV_2
#pragma config FPBDIV = DIV_1
#pragma config FWDTEN = OFF

#define SYS_FREQ (80000000L)
#define PB_DIV 1
#define PRESCALE 256
#define SAMPLING_RATE (SYS_FREQ/PB_DIV/PRESCALE)

#define OLED_CMD 0x00
#define OLED_DATA 0x40

void initADC(void);
void initOLED(void);
void plotWaveform(void);

unsigned char waveformBuffer[128];

int main(void)
{
initADC();
initOLED();

while (1)
{
      plotWaveform();
}

return 0;
}

void initADC(void)
{
AD1PCFG = 0xFFFF; // All pins digital
AD1CON1 = 0x00E0; // Auto-convert mode
AD1CSSL = 0x0000; // No scanning required
AD1CON2 = 0x0000; // No scanning required
AD1CON3 = 0x1F00; // Tad = 32 PBCLK cycles
AD1CON1bits.ADON = 1; // Turn on ADC
}

void initOLED(void)
{
// Initialize SPI1 module
SPI1CONbits.ON = 0;    // Disable SPI module
SPI1CONbits.MSTEN = 1;  // Set as Master mode
SPI1CONbits.CKE = 1; // Clock edge select
SPI1CONbits.SMP = 0; // Input data sampled at middle of data output time
SPI1CONbits.MODE16 = 0; // 8-bit mode
SPI1CONbits.MODE32 = 0; // 8-bit mode
SPI1CONbits.DISSDI = 0; // Enable SDI pin
SPI1CONbits.DISSDO = 0; // Enable SDO pin
SPI1CONbits.SSEN = 0; // SS pin not used
SPI1CONbits.ENHBUF = 1; // Enable enhanced buffer mode
SPI1CONbits.MCLKSEL = 0;// Set PBCLK as SPI clock
SPI1BRG = 0;          // Set clock divider to 1
SPI1CONbits.ON = 1;    // Enable SPI module

// Initialize OLED module
TRISDbits.TRISD9 = 0; // Set RD9 as output (data/command pin)
TRISGbits.TRISG6 = 0; // Set RG6 as output (reset pin)
PORTGbits.RG6 = 1;    // Set OLED reset pin high
DelayMs(1);          // Wait for OLED to stabilize
PORTGbits.RG6 = 0;    // Set OLED reset pin low
DelayMs(10);          // Wait for OLED to reset
PORTGbits.RG6 = 1;    // Set OLED reset pin high

// Initialize OLED display
WriteOLEDCommand(0xAE);  // Display off
WriteOLEDCommand(0xA1);  // Segment remap
WriteOLEDCommand(0xDA);  // Common pads hardware: alternative
WriteOLEDCommand(0x12);
WriteOLEDCommand(0xC8);  // Common output scan direction:com63~com0
WriteOLEDCommand(0D5,D4 display multiplex, D3 disable to display clock, D2~D0normal)
WriteOLEDCommand(0x81);  // Contrast control
WriteOLEDCommand(0xCF);
WriteOLEDCommand(0xD9);  // Set pre-charge period
WriteOLEDCommand(0xF1);
WriteOLEDCommand(0xDB);  // VCOM deselect level mode
WriteOLEDCommand(0x40);
WriteOLEDCommand(0xA4);  // Set display mode: Reset
WriteOLEDCommand(0xA6);  // Set display mode: Normal display
WriteOLEDCommand(0xAF);  // Display on
}

void plotWaveform(void)
{
int i;

// Sample analog inputs
AD1CON1bits.SAMP = 1; // Start sampling
DelayUs(10);          // Wait for sampling to complete
AD1CON1bits.SAMP = 0; // Stop sampling and start conversion
while (!AD1CON1bits.DONE);  // Wait for conversion to complete
int adcValues[4];
adcValues[0] = ADC1BUF0;
adcValues[1] = ADC1BUF1;
adcValues[2] = ADC1BUF2;
adcValues[3] = ADC1BUF3;

// Convert ADC values to waveform buffer
for (i = 0; i < 128; i++)
{
      int sum = 0;
      int j;
      for (j = 0; j < 4; j++)
      {
         AD1CHSbits.CH0SA = j; // Select analog input channel
         AD1CON1bits.SAMP = 1; // Start sampling
         DelayUs(10);          // Wait for sampling to complete
         AD1CON1bits.SAMP = 0; // Stop sampling and start conversion
         while (!AD1CON1bits.DONE);  // Wait for conversion to complete
         sum += ADC1BUF0;
      }
      waveformBuffer[i] = sum / 4;
}

// Display waveform on OLED
WriteOLEDCommand(0xAE);    // Display off
WriteOLEDCommand(0x20);    // Set memory addressing mode
WriteOLEDCommand(0x10);    // Set horizontal addressing mode
WriteOLEDCommand(0xB0);    // Set page start address
WriteOLEDCommand(0x00);    // Set lower column address
WriteOLEDCommand(0x10);    // Set higher column address
for (i = 0; i < 128; i++)
{
      WriteOLEDData(waveformBuffer[i]);
}
WriteOLEDCommand(0xAF);    // Display on
}

void WriteOLEDCommand(unsigned char command)
{
LATDbits.LATD9 = OLED_CMD;
while (SPI1STATbits.SPITBF); // Wait for TX buffer to be empty
SPI1BUF = command;          // Send command
while (!SPI1STATbits.SPIRBF);// Wait for RX buffer to be full
char dummy = SPI1BUF;       // Discard received data
}

void WriteOLEDData(unsigned char data)
{
LATDbits.LATD9 = OLED_DATA;
while (SPI1STATbits.SPITBF); // Wait for TX buffer to be empty
SPI1BUF = data;
while (!SPI1STATbits.SPIRBF);// Wait for RX buffer to be full
char dummy = SPI1BUF;       // Discard received data
}

void DelayUs(unsigned int us)
{
// Convert us to timer ticks
us *= PBCLK / 1000000;

// Use Timer 2 to generate delay
T2CONbits.TCKPS = 0;       // Set prescaler to 1
T2CONbits.T32 = 0;       // Timer 2 operates as two 16-bit timers
T2CONbits.TCS = 0;       // Use internal clock
TMR2 = 0;                // Reset timer
PR2 = us;                // Set period
T2CONbits.TON = 1;       // Turn on timer

// Wait for timer to expire
while (!IFS0bits.T2IF);

T2CONbits.TON = 0;       // Turn off timer
IFS0bits.T2IF = 0;       // Clear interrupt flag
}

int main(void)
{
TRISB = 0xFFFF; // Set all PORTB pins as inputs
TRISD = 0; // Set all PORTD pins as outputs
LATD = 0; // Clear all PORTD outputs

// Configure SPI1 for OLED communication
SPI1CONbits.ON = 0;       // Turn off SPI1
SPI1CONbits.MSTEN = 1;    // Master mode
SPI1CONbits.CKP = 0;       // Idle clock low
SPI1CONbits.CKE = 1;       // Data changes on falling edge
SPI1CONbits.SMP = 0;       // Sample data on rising edge
SPI1CONbits.MODE16 = 0;    // 8-bit mode
SPI1CONbits.MODE32 = 0;    // 8-bit mode
SPI1CONbits.DISSDO = 0;    // SDO1 enabled
SPI1CONbits.DISSDI = 1;    // SDI1 disabled
SPI1CONbits.SSEN = 0;    // SS1 pin not used
SPI1CONbits.ENHBUF = 0;    // Standard buffer mode
SPI1CONbits.MCLKSEL = 0; // PBCLK used as clock source
SPI1BRG = 0;             // Maximum baud rate
SPI1CONbits.ON = 1;       // Turn on SPI1

// Configure Timer 2 for delay function
T2CONbits.ON = 0;          // Turn off Timer 2
T2CONbits.TCKPS = 0;       // Set prescaler to 1
T2CONbits.T32 = 0;       // Timer 2 operates as two 16-bit timers
T2CONbits.TCS = 0;       // Use internal clock
TMR2 = 0;                // Reset timer
PR2 = 0xFFFF;             // Set period to maximum
T2CONbits.ON = 1;          // Turn on Timer 2

// Configure analog inputs for ADC
AD1PCFG = 0xFFFF;          // Set all pins as digital
AD1CON1bits.ADON = 0;    // Turn off ADC1
AD1CON1bits.FORM = 0;    // Integer format
AD1CON1bits.SSRC = 0b111; // Auto-
AD1CON1bits.ASAM = 1;    // Auto-start sampling
AD1CON2bits.VCFG = 0;    // Use AVDD and AVSS as reference
AD1CON2bits.CSCNA = 1;    // Scan inputs
AD1CON2bits.SMPI = 3;    // Interrupt after 4 conversions
AD1CON2bits.BUFM = 0;    // Use 16-word buffer
AD1CON2bits.ALTS = 0;    // Always use MUXA
AD1CON3bits.ADRC = 0;    // Use PBCLK as clock source
AD1CON3bits.SAMC = 0b11111; // 31 Tad
AD1CON3bits.ADCS = 1;    // Set Tad to 2x Tpb
AD1CHSbits.CH0NA = 0;    // Use Vref- as negative input
AD1CON1bits.ADON = 1;    // Turn on ADC1

// Configure Timer 3 for PWM output
T3CONbits.ON = 0;          // Turn off Timer 3
T3CONbits.TCKPS = 0;       // Set prescaler to 1
T3CONbits.TCS = 0;       // Use internal clock
T3CONbits.TGATE = 0;       // Disable gated mode
T3CONbits.TSIDL = 0;       // Continue operation in idle mode
T3CONbits.TSYNC = 0;       // Do not sync external clock input
TMR3 = 0;                // Reset timer
PR3 = 3999;                // Set period to 4ms
OC1R = 0;                // Clear duty cycle
OC1RS = 2000;             // Set initial duty cycle to 50%
OC1CONbits.OCTSEL = 1;    // Use Timer 3 for output compare
OC1CONbits.OCM = 0b110;    // PWM mode
T3CONbits.ON = 1;          // Turn on Timer 3

while (1)
{
// Start ADC conversion
AD1CON1bits.SAMP = 1;
DelayUs(10);
AD1CON1bits.SAMP = 0;

// Wait for ADC conversion to complete
while (!IFS0bits.AD1IF);

// Read ADC result and display on OLED
int i;
for (i = 0; i < 4; i++)
{
      char str[10];
      sprintf(str, "%04d", ADC1BUF[i]);
      DrawString(10 + i * 60, 20, str, WHITE, BLACK);
}

// Update PWM duty cycle based on ADC value
OC1RS = ADC1BUF[0] / 4;

// Clear ADC interrupt flag
IFS0bits.AD1IF = 0;
}

return 0;
}

程式碼主要功能是使用 PIC32MX440F256H 微控制器的 ADC 模塊和 PWM 模塊。

在這段程式碼中，首先使用 ADC 模塊來採樣四個通道的模擬信號，並使用 OLED 顯示每個通道的數值。
然後，根據其中一個通道的數值，更新 PWM 模塊的佔空比，以產生 PWM 輸出信號。

具體來說，以下是每個主要設置的解釋：

AD1CON1bits.ASAM = 1;：啟用自動採樣模式，讓 ADC 自動開始採樣。
AD1CON2bits.VCFG = 0;：將 AVDD 和 AVSS 設置為 ADC 參考電壓。
AD1CON2bits.CSCNA = 1;：啟用通道掃描模式，讓 ADC 自動掃描多個通道。
AD1CON2bits.SMPI = 3;：設置中斷標誌觸發時的掃描數量，此處設置為 4。
AD1CON2bits.BUFM = 0;：使用 16 個單詞緩存。
AD1CON2bits.ALTS = 0;：始終使用 MUXA。
AD1CON3bits.ADRC = 0;：使用 PBCLK 作為 ADC 時鐘源。
AD1CON3bits.SAMC = 0b11111;：設置採樣時間，此處為 31 Tad。
AD1CON3bits.ADCS = 1;：設置 ADC 時鐘分頻，此處設置為 2x Tpb。
AD1CHSbits.CH0NA = 0;：使用 Vref- 作為負輸入。
AD1CON1bits.ADON = 1;：啟用 ADC1。
以上設置將 ADC1 設置為掃描模式，自動採樣四個通道，並將採樣結果存儲在 ADC1BUF 中。

接下來，使用 Timer 3 和 Output Compare 模塊來生成 PWM 輸出信號。
具體來說：

T3CONbits.ON = 0;：關閉 Timer 3。
T3CONbits.TCKPS = 0;：設置計時器分頻器，此處設置為 1。
T3CONbits.TCS = 0;：使用內部時鐘源。
T3CONbits.TGATE = 0;：禁用門控模式。
T3CONbits.TSIDL = 0;：在空閒模式下