/* * Copyright 2013-2014 Ettus Research LLC * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ /* * Welcome to the firmware code for the USRP Octoclock accessory product! * * Notes regarding this firmware: * NOT in M103 compatibility mode * CKOPT full rail-to-rail * xtal osc * 16K CK (16K clock cycles) * additional delay 65ms for Crystal Oscillator * slowly rising power * persistent EEPROM * * These settings are very conservative. If a lower power oscillator is * required, change CKOPT to '1' (UNPROGRAMMED). * * M103C = [ ] * WDTON = [ ] * OCDEN = [ ] * JTAGEN = [X] * SPIEN = [X] * EESAVE = [X] * BOOTSZ = 4095W_F000 * BOOTRST = [ ] * CKOPT = [X] * BODLEVEL = 2V7 * BODEN = [ ] * SUT_CKSEL = EXTHIFXTALRES_16KCK_64MS * * EXTENDED = 0xFF (valid) * HIGH = 0x81 (valid) * LOW = 0xFF (valid) * */ #include <stdlib.h> #include <string.h> #include <stdint.h> #include <stdbool.h> #include <avr/eeprom.h> #include <avr/interrupt.h> #include <avr/io.h> #include <avrlibdefs.h> #include <octoclock.h> #include <debug.h> #include <clkdist.h> #include <state.h> #include <network.h> #include <usart.h> #include <net/udp_handlers.h> /* * Timer 3 (16-bit) * * Set input capture trigger to rising edge * * Set prescaler to 1 * * Enable overflow interrupt * * Set timer to 0 */ #define TIMER3_INIT() TCCR3B = (1 << ICES3) | (1 << CS30); \ ETIMSK |= (1 << TOIE3); \ TCNT3 = 0; \ ICR3 = 0; /* * We use TIMER3 as a watchdog timer for external reference * detection. Once a signal is detected, we allow for five * timer overflows (~26 ms) without another signal before * deciding that there is no external reference connected. */ #define EXT_REF_TIMEOUT 5 static volatile uint16_t num_overflows = 0; static uint16_t current_num_overflows = 0; static uint16_t prev_num_overflows = 0; static uint16_t current_ICR3 = 0; static uint16_t prev_ICR3 = 0; static ref_t prev_ref = NO_REF; static switch_pos_t prev_switch_pos = PREFER_EXTERNAL; bool top = false; ISR(TIMER3_OVF_vect){ num_overflows++; } /******************************************************************************* * Main Routine *******************************************************************************/ int main(void){ /* * Initializations */ cli(); // Make sure interrupts belong to us MCUCR = (1<<IVCE); MCUCR = 0; // Initialize global variables g_ext_ref_present = false; g_gps_present = false; g_switch_pos = PREFER_INTERNAL; g_ref = NO_REF; // Atmega128 setup_atmel_io_ports(); // Reset ClkDist chip reset_TI_CDCE18005(); // GPSDO communication usart_init(); // Ethernet stack network_init(); register_udp_listener(OCTOCLOCK_UDP_CTRL_PORT, handle_udp_ctrl_packet); register_udp_listener(OCTOCLOCK_UDP_GPSDO_PORT, handle_udp_gpsdo_packet); // Timers TIMER1_INIT(); // Network TIMER3_INIT(); // External reference check // Debug (does nothing when not in debug mode) DEBUG_INIT(); DEBUG_LOG(" "); // Force a newline between runs leds_off(); sei(); // Check if GPS present (should only need to happen once) g_gps_present = (PIND & (1<<DDD4)); // State of previous iteration prev_ref = NO_REF; prev_switch_pos = PREFER_EXTERNAL; cli(); prev_ICR3 = ICR3; sei(); prev_num_overflows = 0; /* * Main loop */ while(true){ // Check switch position g_switch_pos = (PINC & (1<<DDC1)) ? PREFER_EXTERNAL : PREFER_INTERNAL; /* * Check input capture pin for external reference detection. * * 16-bit reads could be corrupted during an interrupt, so * disable interrupts for safety. */ cli(); current_ICR3 = ICR3; current_num_overflows = num_overflows; sei(); // Signal detected, reset timer if(current_ICR3 != prev_ICR3){ cli(); TCNT3 = 0; num_overflows = 0; sei(); g_ext_ref_present = true; } // Timeout, no external reference detected if(current_num_overflows >= EXT_REF_TIMEOUT){ g_ext_ref_present = false; } // Determine and set reference based on state if(!g_gps_present && !g_ext_ref_present) g_ref = NO_REF; else if(g_gps_present && !g_ext_ref_present) g_ref = INTERNAL; else if(!g_gps_present && g_ext_ref_present) g_ref = EXTERNAL; else g_ref = (g_switch_pos == PREFER_INTERNAL) ? INTERNAL : EXTERNAL; if((g_ref != prev_ref) || (g_switch_pos != prev_switch_pos)){ if(g_switch_pos == PREFER_INTERNAL) prefer_internal(); else prefer_external(); } // Record this iteration's state prev_ref = g_ref; prev_switch_pos = g_switch_pos; prev_ICR3 = current_ICR3; prev_num_overflows = current_num_overflows; // Handle incoming Ethernet packets network_check(); } }