📄 c8051spi.c
字号:
//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------
#include <c8051f020.h> // SFR declarations
#include <stdio.h>
//-----------------------------------------------------------------------------
// 16-bit SFR Definitions for 'F02x
//-----------------------------------------------------------------------------
sfr16 DP = 0x82; // data pointer
sfr16 TMR3RL = 0x92; // Timer3 reload value
sfr16 TMR3 = 0x94; // Timer3 counter
sfr16 ADC0 = 0xbe; // ADC0 data
sfr16 ADC0GT = 0xc4; // ADC0 greater than window
sfr16 ADC0LT = 0xc6; // ADC0 less than window
sfr16 RCAP2 = 0xca; // Timer2 capture/reload
sfr16 T2 = 0xcc; // Timer2
sfr16 RCAP4 = 0xe4; // Timer4 capture/reload
sfr16 T4 = 0xf4; // Timer4
sfr16 DAC0 = 0xd2; // DAC0 data
sfr16 DAC1 = 0xd5; // DAC1 data
//-----------------------------------------------------------------------------
// Global CONSTANTS
//-----------------------------------------------------------------------------
#define SYSCLK 22118400 // SYSCLK frequency in Hz
#define BAUDRATE 115200 // Baud rate of UART in bps
sbit LED = P1^6; // LED='1' means ON
sbit EE_CS = P1^7; // EEPROM CS signal
#define EE_SIZE 4096 // EEPROM size in bytes
#define EE_READ 0x03 // EEPROM Read command
#define EE_WRITE 0x02 // EEPROM Write command
#define EE_WRDI 0x04 // EEPROM Write disable command
#define EE_WREN 0x06 // EEPROM Write enable command
#define EE_RDSR 0x05 // EEPROM Read status register
#define EE_WRSR 0x01 // EEPROM Write status register
//-----------------------------------------------------------------------------
// Function PROTOTYPES
//-----------------------------------------------------------------------------
void SYSCLK_Init (void);
void PORT_Init (void);
void UART0_Init (void);
void SPI0_Init (void);
void Timer0_ms (unsigned ms);
void Timer0_us (unsigned us);
unsigned char EE_Read (unsigned Addr);
void EE_Write (unsigned Addr, unsigned char value);
//-----------------------------------------------------------------------------
// Global VARIABLES
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// MAIN Routine
//-----------------------------------------------------------------------------
void main (void) {
unsigned EE_Addr; // address of EEPROM byte
unsigned char test_byte;
WDTCN = 0xde; // disable watchdog timer
WDTCN = 0xad;
SYSCLK_Init (); // initialize oscillator
PORT_Init (); // initialize crossbar and GPIO
UART0_Init (); // initialize UART0
SPI0_Init (); // initialize SPI0
// fill EEPROM with 0xFF's
LED = 1;
for (EE_Addr = 0; EE_Addr < EE_SIZE; EE_Addr++) {
test_byte = 0xff;
EE_Write (EE_Addr, test_byte);
// print status to UART0
if ((EE_Addr % 16) == 0) {
printf ("\nwriting 0x%04x: %02x ", EE_Addr, (unsigned) test_byte);
} else {
printf ("%02x ", (unsigned) test_byte);
}
}
// verify EEPROM with 0xFF's
LED = 0;
for (EE_Addr = 0; EE_Addr < EE_SIZE; EE_Addr++) {
test_byte = EE_Read (EE_Addr);
// print status to UART0
if ((EE_Addr % 16) == 0) {
printf ("\nverifying 0x%04x: %02x ", EE_Addr, (unsigned) test_byte);
} else {
printf ("%02x ", (unsigned) test_byte);
}
if (test_byte != 0xFF) {
printf ("Error at %u\n", EE_Addr);
while (1); // stop here on error
}
}
// fill EEPROM memory with LSB of EEPROM address.
LED = 1;
for (EE_Addr = 0; EE_Addr < EE_SIZE; EE_Addr++) {
test_byte = EE_Addr & 0xff;
EE_Write (EE_Addr, test_byte);
// print status to UART0
if ((EE_Addr % 16) == 0) {
printf ("\nwriting 0x%04x: %02x ", EE_Addr, (unsigned) test_byte);
} else {
printf ("%02x ", (unsigned) test_byte);
}
}
// verify EEPROM memory with LSB of EEPROM address
LED = 0;
for (EE_Addr = 0; EE_Addr < EE_SIZE; EE_Addr++) {
test_byte = EE_Read (EE_Addr);
// print status to UART0
if ((EE_Addr % 16) == 0) {
printf ("\nverifying 0x%04x: %02x ", EE_Addr, (unsigned) test_byte);
} else {
printf ("%02x ", (unsigned) test_byte);
}
if (test_byte != (EE_Addr & 0xFF)) {
printf ("Error at %u\n", EE_Addr);
while (1); // stop here on error
}
}
while (1) { // Flash LED when done
Timer0_ms (100);
LED = ~LED;
}
}
//-----------------------------------------------------------------------------
// Subroutines
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// SYSCLK_Init
//-----------------------------------------------------------------------------
//
// This routine initializes the system clock to use an 22.1184 MHz crystal
// as its clock source.
//
void SYSCLK_Init (void)
{
int i; // delay counter
OSCXCN = 0x67; // start external oscillator with
// 22.1184 MHz crystal
for (i=0; i < 256; i++) ; // Wait for osc. to start up
while (!(OSCXCN & 0x80)) ; // Wait for crystal osc. to settle
OSCICN = 0x88; // select external oscillator as SYSCLK
// source and enable missing clock
// detector
}
//-----------------------------------------------------------------------------
// PORT_Init
//-----------------------------------------------------------------------------
//
// Configure the Crossbar and GPIO ports
//
void PORT_Init (void)
{
XBR0 |= 0x06; // Enable SPI0 and UART0
XBR1 = 0x00;
XBR2 = 0x40; // Enable crossbar and weak pull-ups
P0MDOUT |= 0x15; // enable P0.0 (TX), P0.2 (SCK), and
// P0.4 (MOSI) as push-pull outputs
P1MDOUT |= 0xC0; // enable P1.6 (LED) and P1.7 (EE_CS)
// as push-pull outputs
}
//-----------------------------------------------------------------------------
// SPI0_Init
//-----------------------------------------------------------------------------
void SPI0_Init (void)
{
SPI0CFG = 0x07; // data sampled on 1st SCK rising edge
// 8-bit data words
SPI0CN = 0x03; // Master mode; SPI enabled; flags
// cleared
SPI0CKR = SYSCLK/2/2000000; // SPI clock <= 2MHz (limited by
// EEPROM spec.)
}
//-----------------------------------------------------------------------------
// UART0_Init
//-----------------------------------------------------------------------------
//
// Configure the UART0 using Timer1, for <baudrate> and 8-N-1.
//
void UART0_Init (void)
{
SCON0 = 0x50; // SCON0: mode 1, 8-bit UART, enable RX
TMOD = 0x20; // TMOD: timer 1, mode 2, 8-bit reload
TH1 = -(SYSCLK/BAUDRATE/16); // set Timer1 reload value for baudrate
TR1 = 1; // start Timer1
CKCON |= 0x10; // Timer1 uses SYSCLK as time base
PCON |= 0x80; // SMOD00 = 1 (disable baud rate
// divide-by-two)
TI0 = 1; // Indicate TX0 ready
}
//-----------------------------------------------------------------------------
// Timer0_ms
//-----------------------------------------------------------------------------
//
// Configure Timer0 to delay <ms> milliseconds before returning.
//
void Timer0_ms (unsigned ms)
{
unsigned i; // millisecond counter
TCON &= ~0x30; // STOP Timer0 and clear overflow flag
TMOD &= ~0x0f; // configure Timer0 to 16-bit mode
TMOD |= 0x01;
CKCON |= 0x08; // Timer0 counts SYSCLKs
for (i = 0; i < ms; i++) { // count milliseconds
TR0 = 0; // STOP Timer0
TH0 = (-SYSCLK/1000) >> 8; // set Timer0 to overflow in 1ms
TL0 = -SYSCLK/1000;
TR0 = 1; // START Timer0
while (TF0 == 0); // wait for overflow
TF0 = 0; // clear overflow indicator
}
}
//-----------------------------------------------------------------------------
// Timer0_us
//-----------------------------------------------------------------------------
//
// Configure Timer0 to delay <us> microseconds before returning.
//
void Timer0_us (unsigned us)
{
unsigned i; // millisecond counter
TCON &= ~0x30; // STOP Timer0 and clear overflow flag
TMOD &= ~0x0f; // configure Timer0 to 16-bit mode
TMOD |= 0x01;
CKCON |= 0x08; // Timer0 counts SYSCLKs
for (i = 0; i < us; i++) { // count microseconds
TR0 = 0; // STOP Timer0
TH0 = (-SYSCLK/1000000) >> 8; // set Timer0 to overflow in 1us
TL0 = -SYSCLK/1000000;
TR0 = 1; // START Timer0
while (TF0 == 0); // wait for overflow
TF0 = 0; // clear overflow indicator
}
}
//-----------------------------------------------------------------------------
// EE_Read
//-----------------------------------------------------------------------------
//
// This routine reads and returns a single EEPROM byte whose address is
// given in <Addr>.
//
unsigned char EE_Read (unsigned Addr)
{
unsigned char retval; // value to return
EE_CS = 0; // select EEPROM
EE_CS = 0; // find out why Keil compiler is
// optimizing one of these out
Timer0_us (1); // wait at least 250ns (CS setup time)
// transmit READ opcode
SPIF = 0;
SPI0DAT = EE_READ;
while (SPIF == 0);
// transmit Address MSB-first
SPIF = 0; // transmit MSB of address
SPI0DAT = (Addr >> 8);
while (SPIF == 0);
SPIF = 0; // transmit LSB of address
SPI0DAT = Addr;
while (SPIF == 0);
// initiate dummy transmit to read data
SPIF = 0;
SPI0DAT = 0;
while (SPIF == 0);
retval = SPI0DAT; // read data from SPI
Timer0_us (1); // wait at least 250ns (CS hold time)
EE_CS = 1; // de-select EEPROM
Timer0_us (1); // wait at least 500ns (CS disable time)
return retval;
}
//-----------------------------------------------------------------------------
// EE_Write
//-----------------------------------------------------------------------------
void EE_Write (unsigned Addr, unsigned char value)
{
EE_CS = 0; // select EEPROM
Timer0_us (1); // wait at least 250ns (CS setup time)
// transmit WREN (Write Enable) opcode
SPIF = 0;
SPI0DAT = EE_WREN;
while (SPIF == 0);
Timer0_us (1); // wait at least 250ns (CS hold time)
EE_CS = 1; // de-select EEPROM to set WREN latch
Timer0_us (1); // wait at least 500ns (CS disable
// time)
EE_CS = 0; // select EEPROM
Timer0_us (1); // wait at least 250ns (CS setup time)
// transmit WRITE opcode
SPIF = 0;
SPI0DAT = EE_WRITE;
while (SPIF == 0);
// transmit Address MSB-first
SPIF = 0; // transmit MSB of address
SPI0DAT = (Addr >> 8);
while (SPIF == 0);
SPIF = 0; // transmit LSB of address
SPI0DAT = Addr;
while (SPIF == 0);
// transmit data
SPIF = 0;
SPI0DAT = value;
while (SPIF == 0);
Timer0_us (1); // wait at least 250ns (CS hold time)
EE_CS = 1; // deselect EEPROM (initiate EEPROM
// write cycle)
// now poll Read Status Register (RDSR) for Write operation complete
do {
Timer0_us (1); // wait at least 500ns (CS disable
// time)
EE_CS = 0; // select EEPROM to begin polling
Timer0_us (1); // wait at least 250ns (CS setup time)
SPIF = 0;
SPI0DAT = EE_RDSR; // send Read Status register opcode
while (SPIF == 0);
SPIF = 0;
SPI0DAT = 0; // dummy write to read status register
while (SPIF == 0);
Timer0_us (1); // wait at least 250ns (CS hold
// time)
EE_CS = 1; // de-select EEPROM
} while (SPI0DAT & 0x01); // poll until WIP (Write In
// Progress) bit goes to '0'
Timer0_us (1); // wait at least 500ns (CS disable
// time)
}⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -