Add prototyping code for sending a dummy message with the nrf24l01

The firmware is developed using an aduino micro pro with an atmega32u4
as the hardware for the weather station is not ready yet.

weather-sensor/firmware/.gitignore

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+main
+*.hex

weather-sensor/firmware/compile.sh

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+make main
+make main.hex

weather-sensor/firmware/main.c

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+//#define F_CPU 1000000UL  // Frequenz des Quarzes, ohne Quarz standardmäßig 1MHz
+
+#include <avr/io.h>
+#include <util/delay.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "nrf24l01.h"
+#include "uart_debug.h"
+
+//#define LED_DDR     DDRB        //DDRA, DDRB...
+//#define LED_PORT    PORTB       //PORTA, PORTB...
+//#define LED_PORTPIN PB0         //PA0, PA1..., PB0, PB1..., ...
+//#define time_off    8
+
+/* SPI: */
+#define SPI_DDR       DDRB
+#define SPI_SCK_PIN   PB1
+#define SPI_MOSI_PIN  PB2
+#define SPI_MISO_PIN  PB3
+
+/* NRF24L01 */
+
+
+
+/*
+ * CS: pin 9
+ * CE: pin 8
+ * IRQ: pin 7
+ */
+
+
+
+char bool_case = 0;
+int timer = 0;
+int timer_max = 0;
+
+
+void Initialize_SPI(void);
+
+int main (void)
+{
+	char debugString[50] = "";
+//	uint8_t testRegisterContent = 0x0A;
+//	uint8_t registerContent[5];
+//	char registerContentString[30];
+//	uint8_t lengthRead;
+
+	/* Set baud rate */
+	Initialize_UART(51);
+
+	sprintf(debugString, "%s\r\n", "Program start");
+	Print_Debug_String(debugString);
+
+	/* Initialize the SPI */
+	Initialize_SPI();
+
+	/* Initialize the nrf24l01 */
+	Initialize_NRF24L01();
+	// The NRF24L01 is now in the mode Standby-I.
+
+	/* Configure the transmission parameters (Enhanced ShockBurst)*/
+	Configure_Transmission();
+
+
+
+
+
+
+
+//	sprintf(debugString, "%s\r\n", "program end");
+//	Print_Debug_String(debugString);
+
+	while(1)
+	{
+		Send_Test_Message();
+		sprintf(debugString, "%s\r\n", "test message");
+		Print_Debug_String(debugString);
+		_delay_ms(1000);
+	}
+}
+
+void Initialize_SPI(void)
+{
+	/* Set MOSI and SCK output, all others input */
+	SPI_DDR = (1<<SPI_MOSI_PIN)|(1<<SPI_SCK_PIN);
+	/* Enable SPI, Master, set clock rate fck/16 */
+	SPCR = (1<<SPE)|(1<<MSTR);
+}

weather-sensor/firmware/makefile

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+all: main.hex
+
+clean:
+	rm -f main.hex
+	rm -f main
+
+flash: main.hex
+	sudo avrdude -c avr109 -b 57600 -P /dev/ttyACM0 -p m32u4 -v -U flash:w:main.hex
+
+main: main.c nrf24l01.c nrf24l01.h uart_debug.c uart_debug.h
+	avr-gcc main.c nrf24l01.c uart_debug.c  -o main -mmcu=atmega32u4 -Os -Wall -Wextra -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -DF_CPU=8000000UL
+
+main.hex: main
+	avr-objcopy -O ihex -R .eeprom main main.hex

weather-sensor/firmware/nrf24l01.c

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+#include <stdint.h>
+#include <avr/io.h>
+#include <util/delay.h>
+#include <stdio.h>
+#include <stdbool.h>
+
+#include "nrf24l01.h"
+#include "uart_debug.h"
+
+/* TODO
+ * - Build a state machine that tracks the mode the NRF is set to
+ * - Configuration of NRF24L01 and startup
+ * - Send and Receive functions
+ * - Interrupt handling for Send and Receive
+ */
+
+void Print_Register_Contents(uint8_t address);
+
+/* Startup and initial configuration of the NRF24L01 */
+void Initialize_NRF24L01(void)
+{
+	/* Configure the AVR pins for the nrf24l01 */
+	/* Set up the NRF24L01 */
+	NRF_CE_DDR |= (1 << NRF_CE_PIN);
+	NRF_CSN_DDR |= (1 << NRF_CSN_PIN);
+
+	NRF_CSN_PORT |= (1 << NRF_CSN_PIN);
+
+	/* Ensure that the CE pin is set to 0*/
+	NRF_CE_PORT &= ~(1 << NRF_CE_PIN);
+
+	/* Wait more than 10.3 ms to make sure the nrf24l01 is running */
+	_delay_ms(11);
+
+	/* Write the PWR_UP bit of the CONFIG register (EN_CRC is also set) */
+	Write_NRF_Register(0x0, 0xA);
+
+	/* Wait more than 1.5 ms for the change to take effect */
+	_delay_ms(2);
+
+	/* The NRF24L01 is now in the mode Standby-I */
+}
+
+void Configure_Transmission(void)
+{
+	/* 
+	 * - Length of CRC (CRCO in CONFIG)
+	 * - Enable auto acknowledgment (EN_AA)
+	 *   -> Register already set correctly after reset
+	 * - Enable data pipes (EN_RXADDR)?
+	 *   -> Two pipes are already enabled on reset
+	 * - Set up address width (SETUP_AW)
+	 *   -> 3 bytes
+	 * - Automatic Retransmission (SETUP_RETR)
+	 *   -> ARD = 0b0000
+	 *   -> 3 retransmits -> ARC = 0b0011
+	 *   -> Register already set correctly after reset
+	 * - RF Channel (RF_CH)
+	 *   -> RF_CH = 0b1010000
+	 * - RF Setup (RF_SETUP)
+	 *   -> first use reset values, can be fine tuned later
+	 * - Enable dynamic payload length (DYNPD) -> command activate + 0x73, then set bits in FEATURE?
+	 */
+
+	/* Set the address width to 3 bytes */
+	//Write_NRF_Register(0x03, 0x1);
+
+	/* Set the frequency to 1450 MHz */
+	Write_NRF_Register(0x05, 0x32);
+
+	/* Enable dynamic payload length */
+	Send_Activate_Command();
+	Write_NRF_Register(0x1D, 0x4); // enable dynamic payload length
+	Write_NRF_Register(0X1C, 0X3F); // set dynamic payload length for all data pipes
+
+	/* Set the TX address */
+	//Set_TX_Address(0x563412);
+	Set_TX_Address(0x123456);
+
+	Set_RX_P0_Address(0x123456);
+	
+
+	// TODO: set addresses for all data pipes
+}
+
+void Send_Test_Message(void)
+{
+	uint8_t buffer[4] = {0xDE, 0xAD, 0xBE, 0xEF};
+	bool transmissionFinished = false;
+	uint8_t statusContent = 0;
+
+	uint8_t registerContent[5];
+	uint8_t lengthRead;
+	char debugString[50] = "";
+	uint32_t timeout = 0;
+	/* TODO:
+	 * - if needed: PRIM_RX = 0
+	 * - Set CE = 1 for more than 10 us
+	 * - Wait until the transmission is finished
+	 * - Read number of retries for debug purposes
+	 * - Check if the FIFO is empty -> if not, flush it
+	 * - reset the interupts of the STATUS
+	 */
+	Write_Message_To_TX_FIFO(4, buffer);
+
+	/* Set CE = 1 for more than 10 us */
+	NRF_CE_PORT |= (1 << NRF_CE_PIN);
+	_delay_us(15);
+	NRF_CE_PORT &= ~(1 << NRF_CE_PIN);
+
+
+	do
+	{
+		_delay_ms(1);
+		lengthRead = Read_NRF_Register(0x07, registerContent);
+
+		if (lengthRead > 1)
+		{
+			sprintf(debugString, "%s\r\n", "read error");
+			Print_Debug_String(debugString);
+		}
+
+		if ((registerContent[0] & (1<<5)) != 0)
+		{
+			transmissionFinished = true;
+			sprintf(debugString, "%s\r\n", "TX fin");
+			Print_Debug_String(debugString);
+		}
+
+		if ((registerContent[0] & (1<<4)) != 0)
+		{
+			transmissionFinished = true;
+			sprintf(debugString, "%s\r\n", "max ret");
+			Print_Debug_String(debugString);
+		}
+		
+		timeout ++;
+	} while ((transmissionFinished == false) && (timeout < 0xFF));
+
+	if (timeout >= 0xFF)
+	{
+			sprintf(debugString, "%s\r\n", "timeout");
+			Print_Debug_String(debugString);
+	}
+
+	/* Reset the interrupts */
+	lengthRead = Read_NRF_Register(0x07, registerContent);
+	statusContent = registerContent[0] & 0x0F;
+	Write_NRF_Register(0x07, statusContent);
+
+	// TODO: flush FIFO if an error occured
+}
+
+void Print_Register_Contents(uint8_t address)
+{
+	uint8_t registerContent[5];
+	uint8_t lengthRead;
+	char debugString[50] = "";
+	char registerContentString[30];
+
+
+	lengthRead = Read_NRF_Register(address, registerContent);
+
+	registerContentString[0] = '\0';
+	for (uint8_t i = 0; i < lengthRead; i++)
+	{
+		sprintf(registerContentString, "%s0x%x ", registerContentString, registerContent[i]);
+	}
+	sprintf(debugString, "%s\r\n", registerContentString);
+	Print_Debug_String(debugString);
+}
+
+
+
+
+/* Send a message:
+ * - Set PRIM_RX = 0 and add one message to the TX-FIFO
+ * - Set CE=1 for more than 10 us
+ * - The NRF takes 130 us to enter the TX Mode
+ * - An Interrupt is generated once the 
+ * - 
+ */
+
+
+/* Set the NRF to RX Mode */
+
+/* Disable the RX Mode */
+
+
+
+
+uint8_t Read_NRF_Status_Register(void)
+{
+	NRF_CSN_PORT &= ~(1 << NRF_CSN_PIN); // Start the transmission
+	SPDR = 0XFF;
+
+	while(!(SPSR & (1<<SPIF))); // Wait for transmission complete
+
+	NRF_CSN_PORT |= (1 << NRF_CSN_PIN); // Stop the transmission
+
+	return SPDR;
+}
+
+uint8_t Read_NRF_Register(uint8_t address, uint8_t * registerContents)
+{
+	uint8_t numberOfBytes = 0;
+
+	if ((address == 0x0A) ||
+	    (address == 0x0B) ||
+	    (address == 0x10))
+	{
+		numberOfBytes = 5;
+	}
+	else
+	{
+		numberOfBytes = 1;
+	}
+
+	/* First write the address */
+	NRF_CSN_PORT &= ~(1 << NRF_CSN_PIN); // Start the transmission
+	SPDR = address;
+
+	while(!(SPSR & (1<<SPIF))); // Wait for transmission complete
+
+	/* Read the register bytes */
+	for (uint8_t i = 0; i < numberOfBytes; i++)
+	{
+		/* Write dummy data to shift in the register content */
+		SPDR = 0x0;
+		while(!(SPSR & (1<<SPIF))); // Wait for transmission complete
+		registerContents[i] = SPDR;
+	}
+
+	NRF_CSN_PORT |= (1 << NRF_CSN_PIN); // Stop the transmission
+
+	// TODO: registers with more than one byte
+	return numberOfBytes;
+}
+
+void Write_NRF_Register(uint8_t address, uint8_t registerContents)
+{
+	/* First write the write command with the address */
+	NRF_CSN_PORT &= ~(1 << NRF_CSN_PIN); // Start the transmission
+	SPDR = address | 0x20;
+	
+	while(!(SPSR & (1<<SPIF))); // Wait for transmission complete
+
+	/* Write the data byte */
+	SPDR = registerContents;
+
+	while(!(SPSR & (1<<SPIF))); // Wait for transmission complete
+
+	NRF_CSN_PORT |= (1 << NRF_CSN_PIN); // Stop the transmission
+}
+
+void Send_Activate_Command(void)
+{
+	/* First write the write command with the address */
+	NRF_CSN_PORT &= ~(1 << NRF_CSN_PIN); // Start the transmission
+	SPDR = 0x50;
+	
+	while(!(SPSR & (1<<SPIF))); // Wait for transmission complete
+
+	/* Write the data byte */
+	SPDR = 0x73;
+
+	while(!(SPSR & (1<<SPIF))); // Wait for transmission complete
+
+	NRF_CSN_PORT |= (1 << NRF_CSN_PIN); // Stop the transmission
+}
+
+
+
+void Write_Message_To_TX_FIFO(uint8_t length, uint8_t * buffer)
+{
+	NRF_CSN_PORT &= ~(1 << NRF_CSN_PIN); // Start the transmission
+
+	/* Issue the write command: */
+	SPDR = 0xA0;
+
+	while(!(SPSR & (1<<SPIF))); // Wait for transmission complete
+
+	/* Write the data bytes */
+	for (uint8_t i = 0; i < length; i++)
+	{
+		SPDR = buffer[i];
+		while(!(SPSR & (1<<SPIF))); // Wait for transmission complete
+	}
+
+	NRF_CSN_PORT |= (1 << NRF_CSN_PIN); // Stop the transmission
+}
+
+void Set_TX_Address(uint32_t txAddress)
+{
+	uint8_t * buffer = (uint8_t*) &txAddress;
+	/* First write the write command with the address */
+	NRF_CSN_PORT &= ~(1 << NRF_CSN_PIN); // Start the transmission
+	SPDR = 0x10 | 0x20;
+	
+	while(!(SPSR & (1<<SPIF))); // Wait for transmission complete
+
+	/* Write the data byte */
+	for (uint8_t i = 0; i < 4; i ++)
+	{
+		SPDR = buffer[i];
+
+		while(!(SPSR & (1<<SPIF))); // Wait for transmission complete
+	}
+
+	SPDR = 0x0;
+
+	while(!(SPSR & (1<<SPIF))); // Wait for transmission complete
+
+	NRF_CSN_PORT |= (1 << NRF_CSN_PIN); // Stop the transmission
+}
+
+void Set_RX_P0_Address(uint32_t rxAddress)
+{
+	uint8_t * buffer = (uint8_t*) &rxAddress;
+	/* First write the write command with the address */
+	NRF_CSN_PORT &= ~(1 << NRF_CSN_PIN); // Start the transmission
+	SPDR = 0x0A | 0x20;
+	
+	while(!(SPSR & (1<<SPIF))); // Wait for transmission complete
+
+	/* Write the data byte */
+	for (uint8_t i = 0; i < 4; i ++)
+	{
+		SPDR = buffer[i];
+
+		while(!(SPSR & (1<<SPIF))); // Wait for transmission complete
+	}
+
+	SPDR = 0x0;
+
+	while(!(SPSR & (1<<SPIF))); // Wait for transmission complete
+
+	NRF_CSN_PORT |= (1 << NRF_CSN_PIN); // Stop the transmission
+}
+
+//TODO: only write the used bytes into the address registers

weather-sensor/firmware/nrf24l01.h

@@ -0,0 +1,25 @@
+#ifndef NRF24L01_H
+#define NRF24L01_H
+
+/* AVR I/O pin definionts */
+#define NRF_CE_DDR   DDRB
+#define NRF_CE_PORT  PORTB
+#define NRF_CE_PIN   PB4
+
+#define NRF_CSN_DDR   DDRB
+#define NRF_CSN_PORT  PORTB
+#define NRF_CSN_PIN   PB5
+
+void Initialize_NRF24L01(void);
+void Configure_Transmission(void);
+uint8_t Read_NRF_Status_Register(void);
+uint8_t Read_NRF_Register(uint8_t address, uint8_t * registerContents);
+void Write_NRF_Register(uint8_t address, uint8_t registerContents);
+void Send_Activate_Command(void);
+
+void Send_Test_Message(void);
+void Write_Message_To_TX_FIFO(uint8_t length, uint8_t * buffer);
+void Set_TX_Address(uint32_t txAddress);
+void Set_RX_P0_Address(uint32_t rxAddress);
+
+#endif

weather-sensor/firmware/uart_debug.c

@@ -0,0 +1,23 @@
+#include <avr/io.h>
+#include <string.h>
+
+#include "uart_debug.h"
+
+void Initialize_UART(uint16_t baudRate)
+{
+	UBRR1H = (unsigned char)(baudRate>>8);
+	UBRR1L = (unsigned char)baudRate;
+	/* Enable receiver and transmitter */
+	UCSR1B = (1<<RXEN1)|(1<<TXEN1);
+	/* Set frame format: 8data, 2stop bit */
+	UCSR1C = (1<<USBS1)|(3<<UCSZ10);
+}
+
+void Print_Debug_String(char * debugString)
+{
+	for (uint8_t i = 0; i < strlen(debugString); i++)
+	{
+		while ( !( UCSR1A & (1<<UDRE1)));
+		UDR1 = debugString[i];
+	}
+}

weather-sensor/firmware/uart_debug.h

@@ -0,0 +1,7 @@
+#ifndef UART_DEBUG_C
+#define UART_DEBUG_C
+
+void Initialize_UART(uint16_t baudRate);
+void Print_Debug_String(char * debugString);
+
+#endif