/*------------------------------------------------------------------------------------------------+ Program: WRT54GL_add_on.c Description: Add on electronics to be incorporated into the housing of a Linksys WRG54GL wireless router. Together with the DD-WRT special firmware for the router, the devices becomes a WLAN client that is able to switch on the connected PC, triggered by a SSH command entered by a remote user. Communication between the AVR and the Broadcom CPU in the WRT54GL is established via the 2nd serial interface of the router (which is only available internally and does not connect to the outside world). As the AVR has many unused inputs (including 6x 10bit ADC inputs), much more applications are left open to be added later. Also there is much space left on the add-on PCB inside the router to add more components. Author: Herbert Dingfelder, DL5NEG Plattform: Atmel AVR ATmega8 Clock-Rate: 3.686 MHz from external Crystal RS232 setting: 9k6 8N1 (default setting of the free serial interface in the WRT54GL) History: 16.12.2008 - Start of development, based on NSLU2 interface software (version 2.0) 17.12.2008 - Serial communication established between WRT and AVR - Commands ATPCB, ATPCOFF and HELP implemented and tested successfully -> Version 1.0 released Pin-Mapping on ATmega8: Pin Port additional Usage in Application ------------------------------------------------------------------------------------------------ 1 PC6 Reset 2 PD0 RXD RS232 RX 3 PD1 TXD RS232 RX 4 PD2 output to red LED (active low) 5 PD3 6 PD4 7 VCC 8 GND 9 PB6 XTAL1 XTAL 10 PB7 XTAL2 XTAL 11 PD5 12 PD6 13 PD7 14 PB0 output to optical coupler to PC power switch (active high) 15 PB1 16 PB2 17 PB3 MOSI 18 PB4 MISO 19 PB5 SCK 20 AVCC 21 AREF 22 GND 23 PC0 24 PC1 25 PC2 26 PC3 27 PC4 28 PC5 -------------------------------------------------------------------------------------------------*/ #include // The io.h already includes the io-avr.h and the iomacros.h !!! // Also the correct address to token (e.g. TIFR = $36) include // file is automatically loaded // (the device must be specified in the makefile!) #include // For storing strings in the flash memory #include // For using interupts, e.g. for incoming RS232 data handling #include // For dealing with strings (arrays of characters) #include // ----- Compiler Switches ----- //#define DEBUG_MODE // Compiler switch for debugging // ----- Defines for better code readability ----- #define CR 13 // ASCII(13) = CR #define LF 10 // ASCII(10) = LF #define UART_BUF_LENGTH 128 // max. 128 characters for command line entrys #define LED_PORT PORTD // red LED is connected to PD2 #define LED_DIR DDRD #define LED_RED _BV(2) #define PC_PORT PORTB // PC power switch is connected to PB0 #define PC_DIR DDRB #define PC_PWR_SW _BV(0) // ----- Global variables ----- char uart_buffer[UART_BUF_LENGTH]; unsigned char uart_pos; // ----- Prototypes for functions ----- void pause(unsigned int n); void reset_handler(void); void send_ser(unsigned char sendbyte); void send_ser_string(char *send_string); void send_help_text(void); // =================================== Main program starts here =================================== int main(void) { reset_handler(); // Initialize all necessary parameters LED_PORT &= ~LED_RED; // switch on LED for 3 seconds pause(3000); LED_PORT |= LED_RED; // switch off LED send_help_text(); // Notivy the host that the AVR is working // and show available commands for(;;); // Endless loop - From now on all actions are triggered // via Interupts from incomming commands via RS232 } //=================================== Subroutines from here on ==================================== //---------------------------------------- reset handler ------------------------------------------ void reset_handler(void) { //------------------- configure GPIOs and set to their default settings ----------------------- LED_DIR |= LED_RED; // configure LED GPIO as output LED_PORT |= LED_RED; // switch off LEDs and switch outputs (output is active low) PC_DIR |= PC_PWR_SW; // configure PC power switch GPIO as output PC_PORT &= ~PC_PWR_SW; // deactive the optical coupler that connects to the PC power switch // (output is active high) //--------------------------- configure UART (RS232-Interfache) ------------------------------- UBRRH = 0; UBRRL = 23; // UART Baudrate 23 => 9k6 at 3.686 MHz ref clock UCSRB = _BV(RXEN) | _BV(TXEN) | _BV(RXCIE); // UART RX and TX on and RX interupt on // (The TX output pin is automatically set as // output by enabling the UART TX) //----------------------------- Enable Interupts in general ----------------------------------- sei(); } //-------------------------------------------- pause ---------------------------------------------- // waits for n milliseconds (pause for 1ms to 65sec) void pause(unsigned int n) { unsigned int t; TCCR0 = 0x03; // 8bit counter on, prescaler factor 64 for( t=0 ; t perform the loop n times { TIFR = _BV(TOV0); // reset the overflow flag for the 8bit counter TCNT0 = 198; // preset the counter to 198 -> 8bit overflow after 1ms while( !( TIFR & _BV(TOV0) ) ); // wait in loop until overflow in timer0 // (i.e. wait for TOV0 Bit is set in TIFR) } } //------------------------------- UART receiver complete interrupt -------------------------------- SIGNAL(SIG_UART_RECV) { unsigned char uart_char='\0'; uart_char=UDR; // read received character from UART input buffer if( uart_char >= 'a' && uart_char <='z' ) // convert lower case characters to upper case, so uart_char -= ( 'a' - 'A' ); // the input is not case-sensitive any more if( uart_pos< (UART_BUF_LENGTH-1) && uart_char>=32) // take over the new character into the buffer { // if the buffer is not full and no ctrl character uart_buffer[uart_pos] = uart_char; uart_pos++; } if( uart_char==LF ) // if the received character was a LF (ASCII 10) which is { // the final termination of a string which is sent from // the WRT54GL with the "echo Text > /dev/tts/1" command // (The the Text a CR + LF is always added automatically) // ----------------------------- check for PC boot command -------------------------------- if( strncmp( uart_buffer, "ATPCB", 5 ) == 0 ) // if the atpcb (= PC boot) command was received { send_ser_string("PC boot command received! \r\n"); // trace output for debugging PC_PORT |= PC_PWR_SW; // activate the optical coupler that connects to the PC power switch LED_PORT &= ~LED_RED; // switch on LED pause(1000); // wait one second (long enough to switch on the PC, // short enough to avoid a forced-off reaction from the PC) PC_PORT &= ~PC_PWR_SW; // deactivate the optical coupler that connects to the PC power switch LED_PORT |= LED_RED; // switch off LED } // ----------------------------- check for PC forced-off command -------------------------- // (This is a emergency command. If the PC does not react any more, it can be forced off by holding // the power switch via the optical coupler for more than 6 seconds. All PCs do a power off then.) if( strncmp( uart_buffer, "ATPCOFF", 7 ) == 0 ) // if the atpcoff (= PC forced off) command was received { send_ser_string("PC forced off command received! \r\n"); // trace output for debugging PC_PORT |= PC_PWR_SW; // activate the optical coupler that connects to the PC power switch LED_PORT &= ~LED_RED; // switch on LED pause(10000); // wait 10 seconds (long enough force the PC off to switch on the PC, // short enough to avoid a forced-off reaction from the PC) PC_PORT &= ~PC_PWR_SW; // deactivate the optical coupler that connects to the PC power switch LED_PORT |= LED_RED; // switch off LED } // ------------------------------------ check for help command ---------------------------- // (This is a emergency command. If the PC does not react any more, it can be forced off by holding // the power switch via the optical coupler for more than 6 seconds. All PCs do a power off then.) if( strncmp( uart_buffer, "HELP", 4 ) == 0 ) // if the help command was received { send_help_text(); LED_PORT &= ~LED_RED; // switch on LED pause(200); // keep it on for a short flash LED_PORT |= LED_RED; // switch off LED } // ---------------------------------------------------------------------------------------- // after a LF we start with a new (empty) buffer at the first postion memset( uart_buffer, ' ', UART_BUF_LENGTH ); // overwrite the uart buffer with all spaces uart_pos = 0; // reset the postion pointer for the uart buffer } } //------------------------------ send one character via RS232 ------------------------------------- // Waits until the TX buffer in the UART is free, then transmits the character void send_ser(unsigned char sendbyte) { while( !(UCSRA & _BV(UDRE) ) ); // wait for UART data register empty UDR = sendbyte; // send the character via UART } // ------------------------------------ send string to RS232 -------------------------------------- void send_ser_string(char *send_string) { char send_char; while( (send_char = *send_string)!='\0' ) { send_ser(send_char); send_string++; } } // --------------------------------- send help text via serial port ------------------------------- void send_help_text(void) { send_ser_string("\r\n\nAVR Mega8 as WRT54GL add-on is alive...\r\n"); send_ser_string("(c) 2008 by Herbert Dingfelder, DL5NEG\r\n\n"); send_ser_string("Available commands:\r\n"); send_ser_string("ATPCB Starts the connected PC\r\n"); send_ser_string("ATPCOFF Forces the PC hard off\r\n"); send_ser_string("HELP Shows this help text\r\n\n"); }