Tweet
Giúp e cái code mikroC này với. E ko hiểu cái chương trình con getADC().
E ko hiểu ngay chỗ
SPI1_Write(0x06);
channel = channel << 6;
tmp = SPI1_Read(channel) & 0x0F;
tmp = tmp << 8;
tmp |= SPI1_Read(0);
tại sao lại viết như vậy?
Bài này là Giao tiếp SPI giữa PIC16f887 với con ADC mcp3204.
Nguyên code của nó đây:
sbit Chip_Select_Direction at TRISC0_bit;
sbit Chip_Select at RC0_bit;
// LCD module connections
sbit LCD_RS at RB5_bit;
sbit LCD_EN at RB7_bit;
sbit LCD_D4 at RB0_bit;
sbit LCD_D5 at RB2_bit;
sbit LCD_D6 at RB4_bit;
sbit LCD_D7 at RB6_bit;
sbit LCD_RS_Direction at TRISB5_bit;
sbit LCD_EN_Direction at TRISB7_bit;
sbit LCD_D4_Direction at TRISB0_bit;
sbit LCD_D5_Direction at TRISB2_bit;
sbit LCD_D6_Direction at TRISB4_bit;
sbit LCD_D7_Direction at TRISB6_bit;
// End LCD module connections
unsigned int measurement, lastValue;
void Init()
{
ANSEL = 0; // Configure AN pins as digital I/O
ANSELH = 0;
C1ON_bit = 0; // Disable comparators
C2ON_bit = 0;
// Init LCD
Lcd_Init();
Lcd_Cmd(_LCD_CLEAR);
Lcd_Cmd(_LCD_CURSOR_OFF);
//
measurement = 0; // Initialize the measurement variable
// Init SPI
SPI1_Init_Advanced(_SPI_MASTER_OSC_DIV64, // Initialize PIC as master
_SPI_DATA_SAMPLE_END, // Data sample at end
_SPI_CLK_IDLE_LOW,
_SPI_LOW_2_HIGH);
Chip_Select_Direction= 0; // ClearBit(TRISC,0)
Chip_Select= 0; // SetBit(PORTC,0)
}
unsigned int getADC(unsigned short channel)
{
// Returns 0..4095
unsigned int tmp;
Chip_Select = 0; // Select MCP3204
SPI1_Write(0x06); // SPI communication using 8-bit segments
channel = channel << 6; // Bits 7 & 6 define ADC input
tmp = SPI1_Read(channel) & 0x0F;
tmp = tmp << 8; // Get ADC value
tmp |= SPI1_Read(0);
Chip_Select = 1;
return tmp;
}
void ProcessValue(unsigned int pv, unsigned short channel)
{ // Writes measured values to LCD
char i, lcdRow, lcdCol;
if(channel < 2) lcdRow=1;
else lcdRow=2;
if(channel%2 > 0 ) lcdCol=13;
else lcdCol=4;
// Converting the measured value into 4 characters
// and writing them to the LCD at the appropriate place
i = pv /1000 + 48;
Lcd_Chr(lcdRow,lcdCol, i);
pv %= 1000;
i = pv /100 + 48;
Lcd_Chr(lcdRow,lcdCol+1, i);
pv %= 100;
i = pv /10 + 48;
Lcd_Chr(lcdRow,lcdCol+2, i);
pv %= 10;
i = pv + 48;
Lcd_Chr(lcdRow,lcdCol+3, i);
}
// main procedure
void main()
{
Init();
// Compilation le
Lcd_Out(1,1,"Build : " __TIME__);
Lcd_Out(2,1,"le " __DATE__);
Delay_ms(2000);
// Initialize SPI and LCD
Lcd_Out(1,1,"C0= C1=");
Lcd_Out(2,1,"C2= C3=");
while(1)
{
measurement = getADC(0); // Get ADC result from Channel 0
ProcessValue(measurement,0); // Writes measured value to LCD
Delay_ms(100); // Wait 100ms
measurement = getADC(1); // Get ADC result from Channel 1
ProcessValue(measurement,1); // Writes measured value to LCD
Delay_ms(100); // Wait 100ms
measurement = getADC(2); // Get ADC result from Channel 2
ProcessValue(measurement,2); // Writes measured value to LCD
Delay_ms(100); // Wait 100ms
measurement = getADC(3); // Get ADC result from Channel 3
ProcessValue(measurement,3); // Writes measured value to LCD
Delay_ms(100); // Wait 100ms
}
}
E ko hiểu ngay chỗ
SPI1_Write(0x06);
channel = channel << 6;
tmp = SPI1_Read(channel) & 0x0F;
tmp = tmp << 8;
tmp |= SPI1_Read(0);
tại sao lại viết như vậy?
Bài này là Giao tiếp SPI giữa PIC16f887 với con ADC mcp3204.
Nguyên code của nó đây:
sbit Chip_Select_Direction at TRISC0_bit;
sbit Chip_Select at RC0_bit;
// LCD module connections
sbit LCD_RS at RB5_bit;
sbit LCD_EN at RB7_bit;
sbit LCD_D4 at RB0_bit;
sbit LCD_D5 at RB2_bit;
sbit LCD_D6 at RB4_bit;
sbit LCD_D7 at RB6_bit;
sbit LCD_RS_Direction at TRISB5_bit;
sbit LCD_EN_Direction at TRISB7_bit;
sbit LCD_D4_Direction at TRISB0_bit;
sbit LCD_D5_Direction at TRISB2_bit;
sbit LCD_D6_Direction at TRISB4_bit;
sbit LCD_D7_Direction at TRISB6_bit;
// End LCD module connections
unsigned int measurement, lastValue;
void Init()
{
ANSEL = 0; // Configure AN pins as digital I/O
ANSELH = 0;
C1ON_bit = 0; // Disable comparators
C2ON_bit = 0;
// Init LCD
Lcd_Init();
Lcd_Cmd(_LCD_CLEAR);
Lcd_Cmd(_LCD_CURSOR_OFF);
//
measurement = 0; // Initialize the measurement variable
// Init SPI
SPI1_Init_Advanced(_SPI_MASTER_OSC_DIV64, // Initialize PIC as master
_SPI_DATA_SAMPLE_END, // Data sample at end
_SPI_CLK_IDLE_LOW,
_SPI_LOW_2_HIGH);
Chip_Select_Direction= 0; // ClearBit(TRISC,0)
Chip_Select= 0; // SetBit(PORTC,0)
}
unsigned int getADC(unsigned short channel)
{
// Returns 0..4095
unsigned int tmp;
Chip_Select = 0; // Select MCP3204
SPI1_Write(0x06); // SPI communication using 8-bit segments
channel = channel << 6; // Bits 7 & 6 define ADC input
tmp = SPI1_Read(channel) & 0x0F;
tmp = tmp << 8; // Get ADC value
tmp |= SPI1_Read(0);
Chip_Select = 1;
return tmp;
}
void ProcessValue(unsigned int pv, unsigned short channel)
{ // Writes measured values to LCD
char i, lcdRow, lcdCol;
if(channel < 2) lcdRow=1;
else lcdRow=2;
if(channel%2 > 0 ) lcdCol=13;
else lcdCol=4;
// Converting the measured value into 4 characters
// and writing them to the LCD at the appropriate place
i = pv /1000 + 48;
Lcd_Chr(lcdRow,lcdCol, i);
pv %= 1000;
i = pv /100 + 48;
Lcd_Chr(lcdRow,lcdCol+1, i);
pv %= 100;
i = pv /10 + 48;
Lcd_Chr(lcdRow,lcdCol+2, i);
pv %= 10;
i = pv + 48;
Lcd_Chr(lcdRow,lcdCol+3, i);
}
// main procedure
void main()
{
Init();
// Compilation le
Lcd_Out(1,1,"Build : " __TIME__);
Lcd_Out(2,1,"le " __DATE__);
Delay_ms(2000);
// Initialize SPI and LCD
Lcd_Out(1,1,"C0= C1=");
Lcd_Out(2,1,"C2= C3=");
while(1)
{
measurement = getADC(0); // Get ADC result from Channel 0
ProcessValue(measurement,0); // Writes measured value to LCD
Delay_ms(100); // Wait 100ms
measurement = getADC(1); // Get ADC result from Channel 1
ProcessValue(measurement,1); // Writes measured value to LCD
Delay_ms(100); // Wait 100ms
measurement = getADC(2); // Get ADC result from Channel 2
ProcessValue(measurement,2); // Writes measured value to LCD
Delay_ms(100); // Wait 100ms
measurement = getADC(3); // Get ADC result from Channel 3
ProcessValue(measurement,3); // Writes measured value to LCD
Delay_ms(100); // Wait 100ms
}
}
Comment