Started rf24 with SPI.

rf24/nRF24L01.h

@@ -0,0 +1,26 @@
+#ifndef NRF24L01_H_
+#define NRF24L01_H_
+
+#define CONFIG      0x00
+#define MASK_RX_DR  6
+#define MASK_TX_DS  5
+#define MASK_MAX_RT 4
+#define EN_CRC      3
+#define CRCO        2
+#define PWR_UP      1
+#define PRIM_RX     0
+
+#define STATUS      0x07
+#define RX_DR       6
+#define TX_DS       5
+#define MAX_RT      4
+#define RX_P_NO     3 // 3 bits
+#define TX_FULL     0
+
+#define R_REGISTER  0x00
+#define W_REGISTER  0x20
+#define REG_MASK    0x1f
+
+// TODO
+
+#endif

rf24/rf24.c

@@ -0,0 +1,91 @@
+#include "rf24.h"
+#include "nRF24L01.h"
+#include "../ard/pins.h"
+
+// FIXME for testing, remove later
+#include <util/delay.h>
+
+const unsigned char RF24_POWER_DOWN = 1;
+const unsigned char RF24_STANDBY_1 = 2;
+const unsigned char RF24_STANDBY_2 = 3;
+const unsigned char RF24_TX = 4;
+const unsigned char RF24_RX = 5;
+
+unsigned char _ce, _csn, _sck, _mo, _mi, _irq;
+
+unsigned char rf24_serial_write(unsigned char);
+
+void rf24_init(unsigned char ce, unsigned char csn, unsigned char sck, unsigned char mo, unsigned char mi, unsigned char irq){
+	pin_mode(ce, OUTPUT);
+	pin_mode(csn, OUTPUT);
+	digital_write(csn, HIGH); // disable
+	pin_mode(sck, OUTPUT);
+	pin_mode(mo, OUTPUT);
+	pin_mode(mi, INPUT);
+	pin_mode(irq, OUTPUT);
+
+	_ce = ce;
+	_csn = csn;
+	_sck = sck;
+	_mo = mo;
+	_mi = mi;
+	_irq = irq;
+
+	rf24_mode(RF24_POWER_DOWN);
+}
+
+void rf24_mode(unsigned char mode){
+	switch(mode){
+		case 1: // RF24_POWER_DOWN
+			rf24_config_register(CONFIG, 0x00);
+			break;
+		case 2: // RF24_STANDBY_1
+			//rf24_config_register(CONFIG, 1<<PWR_UP);
+			break;
+		case 3: // RF24_STANDBY_2
+			break;
+		case 4: // RF24_TX
+			break;
+		case 5: // RF24_RX
+			break;
+	}
+}
+
+void rf24_config_register(unsigned char reg, unsigned char value){
+	rf24_serial_write(W_REGISTER|(reg&REG_MASK));
+	rf24_serial_write(value);
+}
+
+unsigned char rf24_read_register(unsigned char reg){
+	return rf24_serial_write(R_REGISTER|(reg&REG_MASK));
+}
+
+unsigned char rf24_serial_write(unsigned char data){
+	digital_write(_sck, LOW);
+	digital_write(_csn, LOW); // chip enable
+	unsigned char i = 0, rx = 0;
+
+	for(i = 0; i < 8; i++){
+		// write bit
+		if(data&(1<<(7-i))){
+			digital_write(_mo, HIGH);
+		}
+		else{
+			digital_write(_mo, LOW);
+		}
+
+		// read bit
+		digital_write(_sck, HIGH); // clock
+		rx <<= 1;
+
+		if(digital_read(_mi)){
+			rx |= 0x01;
+		}
+
+		digital_write(_sck, LOW); // clock
+	}
+
+	digital_write(_csn, HIGH); // chip disable
+
+	return rx;
+}

rf24/rf24.h

@@ -0,0 +1,16 @@
+#ifndef RF24_H_
+#define RF24_H_
+
+extern const unsigned char RF24_POWER_DOWN;
+extern const unsigned char RF24_STANDBY_1;
+extern const unsigned char RF24_STANDBY_2;
+extern const unsigned char RF24_TX;
+extern const unsigned char RF24_RX;
+
+void rf24_init(unsigned char, unsigned char, unsigned char, unsigned char, unsigned char, unsigned char);
+void rf24_mode(unsigned char);
+
+void rf24_config_register(unsigned char, unsigned char);
+unsigned char rf24_read_register(unsigned char);
+
+#endif