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// read and write eeprom of PIC18F2550 (and 18F2455, 18F4455, 18F4550)
// EEPROM size is 256 bytes
// (c) Raphael Wimmer. Licensed under GNU GPL v2 or higher
#include <pic18f452.h>
//#include <pic18fregs.h>
#include <stdio.h>
#include <usart.h>
#include <adc.h>
code char at __CONFIG1H config1h = 0xFF & _OSC_XT_1H & _OSCS_OFF_1H;
code char at __CONFIG2L config2l = 0xFF & _PUT_ON_2L & _BODEN_OFF_2L & _BODENV_2_7V_2L;
code char at __CONFIG2H config2h = 0xFF & _WDT_OFF_2H;
code char at __CONFIG3H config3h = 0xFF & _CCP2MUX_RC1_3H;
code char at __CONFIG4L config4l = 0xFF & _LVP_OFF_4L & _BACKBUG_ON_4L & _STVR_OFF_4L;
code char at __CONFIG5L config5l = 0xFF & _CP_0_OFF_5L & _CP_1_OFF_5L;
code char at __CONFIG5H config5h = 0xFF & _CPD_OFF_5H & _CPB_OFF_5H;
code char at __CONFIG6L config6l = 0xFF & _WRT_0_OFF_6L & _WRT_1_OFF_6L;
code char at __CONFIG6H config6h = 0xFF & _WRTD_OFF_6H & _WRTB_OFF_6H & _WRTC_OFF_6H;
code char at __CONFIG7L config7l = 0xFF & _EBTR_0_OFF_7L & _EBTR_1_OFF_7L;
code char at __CONFIG7H config7h = 0xFF & _EBTRB_OFF_7H;
#pragma stack 0x300 0xff // set 64 byte stack at 0x300, needed by sdcc
static void isr(void) interrupt 1 {
/*
n Interrupt Vector Interrupt Vector Address
0 RESET vector 0x000000
1 HIGH priority interrupts 0x000008
2 LOW priority interrupts 0x000018
*/
}
void ee_write_byte(unsigned char address, unsigned char *_data){
EEDATA = *_data;
EEADR = address;
// start write sequence as described in datasheet, page 91
EECON1bits.EEPGD = 0;
EECON1bits.CFGS = 0;
EECON1bits.WREN = 1; // enable writes to data EEPROM
INTCONbits.GIE = 0; // disable interrupts
EECON2 = 0x55;
EECON2 = 0x0AA;
EECON1bits.WR = 1; // start writing
while(EECON1bits.WR){
_asm nop _endasm;}
if(EECON1bits.WRERR){
// printf("ERROR: writing to EEPROM failed!\n");
}
EECON1bits.WREN = 0;
INTCONbits.GIE = 1; // enable interrupts
}
void adc_start() {
adc_open(ADC_CHN_1, ADC_FOSC_4, ADC_CFG_5A_0R, ADC_FRM_RJUST);
while (adc_busy()) ;
adc_read();
//unsigned char channel, unsigned char fosc, unsigned char pcfg, unsigned char config
}
void ee_read_byte(unsigned char address, unsigned char *_data){
EEADR = address;
EECON1bits.CFGS = 0;
EECON1bits.EEPGD = 0;
EECON1bits.RD = 1;
*_data = EEDATA;
}
void initUsart()
{
usart_open( // Use USART library to initialise the hardware
USART_TX_INT_OFF
& USART_RX_INT_OFF
& USART_BRGH_HIGH
& USART_ASYNCH_MODE
& USART_EIGHT_BIT,
10 // '10' = 115200 Baud with 20 MHz oscillator and BRGH=1
);
stdout = STREAM_USART;
}
// very simple example. use on an erased eeprom
void main(){
char save_me = 'c';
char from_eeprom;
adc_start();
initUsart();
printf("E");
ee_read_byte(0x00, &from_eeprom);
printf("%c", from_eeprom);
ee_write_byte(0x00, &save_me);
printf("%c", save_me);
ee_read_byte(0x00, &from_eeprom);
printf("%c", from_eeprom);
while (1){}
}
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