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Diffstat (limited to 'src/drivers/ao_aprs.c')
| -rw-r--r-- | src/drivers/ao_aprs.c | 599 |
1 files changed, 599 insertions, 0 deletions
diff --git a/src/drivers/ao_aprs.c b/src/drivers/ao_aprs.c new file mode 100644 index 00000000..6ab61e6a --- /dev/null +++ b/src/drivers/ao_aprs.c @@ -0,0 +1,599 @@ +/** + * http://ad7zj.net/kd7lmo/aprsbeacon_code.html + * + * @mainpage Pico Beacon + * + * @section overview_sec Overview + * + * The Pico Beacon is an APRS based tracking beacon that operates in the UHF 420-450MHz band. The device utilizes a + * Microchip PIC 18F2525 embedded controller, Motorola M12+ GPS engine, and Analog Devices AD9954 DDS. The device is capable + * of generating a 1200bps A-FSK and 9600 bps FSK AX.25 compliant APRS (Automatic Position Reporting System) message. + + + * + * @section history_sec Revision History + * + * @subsection v305 V3.05 + * 23 Dec 2006, Change include; (1) change printf format width to conform to ANSI standard when new CCS 4.xx compiler released. + * + * + * @subsection v304 V3.04 + * 10 Jan 2006, Change include; (1) added amplitude control to engineering mode, + * (2) corrected number of bytes reported in log, + * (3) add engineering command to set high rate position reports (5 seconds), and + * (4) corrected size of LOG_COORD block when searching for end of log. + * + * @subsection v303 V3.03 + * 15 Sep 2005, Change include; (1) removed AD9954 setting SDIO as input pin, + * (2) additional comments and Doxygen tags, + * (3) integration and test code calculates DDS FTW, + * (4) swapped bus and reference analog input ports (hardware change), + * (5) added message that indicates we are reading flash log and reports length, + * (6) report bus voltage in 10mV steps, and + * (7) change log type enumerated values to XORed nibbles for error detection. + * + * + * @subsection v302 V3.02 + * 6 Apr 2005, Change include; (1) corrected tracked satellite count in NMEA-0183 $GPGGA message, + * (2) Doxygen documentation clean up and additions, and + * (3) added integration and test code to baseline. + * + * + * @subsection v301 V3.01 + * 13 Jan 2005, Renamed project and files to Pico Beacon. + * + * + * @subsection v300 V3.00 + * 15 Nov 2004, Change include; (1) Micro Beacon extreme hardware changes including integral transmitter, + * (2) PIC18F2525 processor, + * (3) AD9954 DDS support functions, + * (4) added comments and formatting for doxygen, + * (5) process GPS data with native Motorola protocol, + * (6) generate plain text $GPGGA and $GPRMC messages, + * (7) power down GPS 5 hours after lock, + * (8) added flight data recorder, and + * (9) added diagnostics terminal mode. + * + * + * @subsection v201 V2.01 + * 30 Jan 2004, Change include; (1) General clean up of in-line documentation, and + * (2) changed temperature resolution to 0.1 degrees F. + * + * + * @subsection v200 V2.00 + * 26 Oct 2002, Change include; (1) Micro Beacon II hardware changes including PIC18F252 processor, + * (2) serial EEPROM, + * (3) GPS power control, + * (4) additional ADC input, and + * (5) LM60 temperature sensor. + * + * + * @subsection v101 V1.01 + * 5 Dec 2001, Change include; (1) Changed startup message, and + * (2) applied SEPARATE pragma to several methods for memory usage. + * + * + * @subsection v100 V1.00 + * 25 Sep 2001, Initial release. Flew ANSR-3 and ANSR-4. + * + + + * + * + * @section copyright_sec Copyright + * + * Copyright (c) 2001-2009 Michael Gray, KD7LMO + + + * + * + * @section gpl_sec GNU General Public License + * + * 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 2 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, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + + + * + * + * @section design Design Details + * + * Provides design details on a variety of the components that make up the Pico Beacon. + * + * @subpage power + */ + +/** + * @page power Power Consumption + * + * Measured DC power consumption. + * + * 3VDC prime power current + + * + * 7mA Held in reset + + * 18mA Processor running, all I/O off + + * 110mA GPS running + + * 120mA GPS running w/antenna + + * 250mA DDS running and GPS w/antenna + + * 420mA DDS running, GPS w/antenna, and PA chain on with no RF + + * 900mA Transmit + + * + */ + +#ifndef AO_APRS_TEST +#include <ao.h> +#endif + +#include <ao_aprs.h> + +// Public methods, constants, and data structures for each class. + +static void timeInit(void); + +static void tncInit(void); +static void tnc1200TimerTick(void); + +/** @} */ + +/** + * @defgroup sys System Library Functions + * + * Generic system functions similiar to the run-time C library. + * + * @{ + */ + +/** + * Calculate the CRC-16 CCITT of buffer that is length bytes long. + * The crc parameter allow the calculation on the CRC on multiple buffers. + * + * @param buffer Pointer to data buffer. + * @param length number of bytes in data buffer + * @param crc starting value + * + * @return CRC-16 of buffer[0 .. length] + */ +static uint16_t sysCRC16(const uint8_t *buffer, uint8_t length, uint16_t crc) +{ + uint8_t i, bit, value; + + for (i = 0; i < length; ++i) + { + value = buffer[i]; + + for (bit = 0; bit < 8; ++bit) + { + crc ^= (value & 0x01); + crc = ( crc & 0x01 ) ? ( crc >> 1 ) ^ 0x8408 : ( crc >> 1 ); + value = value >> 1; + } // END for + } // END for + + return crc ^ 0xffff; +} + +/** @} */ + +/** + * @defgroup rtc Real Time Interrupt tick + * + * Manage the built-in real time interrupt. The interrupt clock PRI is 104uS (9600 bps). + * + * @{ + */ + +/// 16-bit NCO where the upper 8-bits are used to index into the frequency generation table. +static uint16_t timeNCO; + +/// Audio tone NCO update step (phase). +static uint16_t timeNCOFreq; + +/** + * Initialize the real-time clock. + */ +static void timeInit() +{ + timeNCO = 0x00; + timeNCOFreq = 0x2000; +} + +/** @} */ + +/** + * @defgroup tnc TNC (Terminal Node Controller) + * + * Functions that provide a subset of the TNC functions. + * + * @{ + */ + +/// The number of start flag bytes to send before the packet message. (360bits * 1200bps = 300mS) +#define TNC_TX_DELAY 45 + +/// The size of the TNC output buffer. +#define TNC_BUFFER_SIZE 40 + +/// States that define the current mode of the 1200 bps (A-FSK) state machine. +typedef enum +{ + /// Stand by state ready to accept new message. + TNC_TX_READY, + + /// 0x7E bit stream pattern used to define start of APRS message. + TNC_TX_SYNC, + + /// Transmit the AX.25 header that contains the source/destination call signs, APRS path, and flags. + TNC_TX_HEADER, + + /// Transmit the message data. + TNC_TX_DATA, + + /// Transmit the end flag sequence. + TNC_TX_END +} TNC_TX_1200BPS_STATE; + +/// AX.25 compliant packet header that contains destination, station call sign, and path. +/// 0x76 for SSID-11, 0x78 for SSID-12 +static uint8_t TNC_AX25_HEADER[] = { + 'A' << 1, 'P' << 1, 'A' << 1, 'M' << 1, ' ' << 1, ' ' << 1, 0x60, \ + 'N' << 1, '0' << 1, 'C' << 1, 'A' << 1, 'L' << 1, 'L' << 1, 0x78, \ + 'W' << 1, 'I' << 1, 'D' << 1, 'E' << 1, '2' << 1, ' ' << 1, 0x65, \ + 0x03, 0xf0 }; + +#define TNC_CALLSIGN_OFF 7 +#define TNC_CALLSIGN_LEN 6 + +static void +tncSetCallsign(void) +{ +#ifndef AO_APRS_TEST + uint8_t i; + + for (i = 0; i < TNC_CALLSIGN_LEN; i++) { + if (!ao_config.callsign[i]) + break; + TNC_AX25_HEADER[TNC_CALLSIGN_OFF + i] = ao_config.callsign[i] << 1; + } + for (; i < TNC_CALLSIGN_LEN; i++) + TNC_AX25_HEADER[TNC_CALLSIGN_OFF + i] = ' ' << 1; +#endif +} + +/// The next bit to transmit. +static uint8_t tncTxBit; + +/// Current mode of the 1200 bps state machine. +static TNC_TX_1200BPS_STATE tncMode; + +/// Counter for each bit (0 - 7) that we are going to transmit. +static uint8_t tncBitCount; + +/// A shift register that holds the data byte as we bit shift it for transmit. +static uint8_t tncShift; + +/// Index into the APRS header and data array for each byte as we transmit it. +static uint8_t tncIndex; + +/// The number of bytes in the message portion of the AX.25 message. +static uint8_t tncLength; + +/// A copy of the last 5 bits we've transmitted to determine if we need to bit stuff on the next bit. +static uint8_t tncBitStuff; + +/// Buffer to hold the message portion of the AX.25 packet as we prepare it. +static uint8_t tncBuffer[TNC_BUFFER_SIZE]; + +/** + * Initialize the TNC internal variables. + */ +static void tncInit() +{ + tncTxBit = 0; + tncMode = TNC_TX_READY; +} + +/** + * Method that is called every 833uS to transmit the 1200bps A-FSK data stream. + * The provides the pre and postamble as well as the bit stuffed data stream. + */ +static void tnc1200TimerTick() +{ + // Set the A-FSK frequency. + if (tncTxBit == 0x00) + timeNCOFreq = 0x2000; + else + timeNCOFreq = 0x3aab; + + switch (tncMode) + { + case TNC_TX_READY: + // Generate a test signal alteranting between high and low tones. + tncTxBit = (tncTxBit == 0 ? 1 : 0); + break; + + case TNC_TX_SYNC: + // The variable tncShift contains the lastest data byte. + // NRZI enocde the data stream. + if ((tncShift & 0x01) == 0x00) { + if (tncTxBit == 0) + tncTxBit = 1; + else + tncTxBit = 0; + } + + // When the flag is done, determine if we need to send more or data. + if (++tncBitCount == 8) + { + tncBitCount = 0; + tncShift = 0x7e; + + // Once we transmit x mS of flags, send the data. + // txDelay bytes * 8 bits/byte * 833uS/bit = x mS + if (++tncIndex == TNC_TX_DELAY) + { + tncIndex = 0; + tncShift = TNC_AX25_HEADER[0]; + tncBitStuff = 0; + tncMode = TNC_TX_HEADER; + } // END if + } else + tncShift = tncShift >> 1; + break; + + case TNC_TX_HEADER: + // Determine if we have sent 5 ones in a row, if we have send a zero. + if (tncBitStuff == 0x1f) + { + if (tncTxBit == 0) + tncTxBit = 1; + else + tncTxBit = 0; + + tncBitStuff = 0x00; + return; + } // END if + + // The variable tncShift contains the lastest data byte. + // NRZI enocde the data stream. + if ((tncShift & 0x01) == 0x00) { + if (tncTxBit == 0) + tncTxBit = 1; + else + tncTxBit = 0; + } + + // Save the data stream so we can determine if bit stuffing is + // required on the next bit time. + tncBitStuff = ((tncBitStuff << 1) | (tncShift & 0x01)) & 0x1f; + + // If all the bits were shifted, get the next byte. + if (++tncBitCount == 8) + { + tncBitCount = 0; + + // After the header is sent, then send the data. + if (++tncIndex == sizeof(TNC_AX25_HEADER)) + { + tncIndex = 0; + tncShift = tncBuffer[0]; + tncMode = TNC_TX_DATA; + } else + tncShift = TNC_AX25_HEADER[tncIndex]; + + } else + tncShift = tncShift >> 1; + + break; + + case TNC_TX_DATA: + // Determine if we have sent 5 ones in a row, if we have send a zero. + if (tncBitStuff == 0x1f) + { + if (tncTxBit == 0) + tncTxBit = 1; + else + tncTxBit = 0; + + tncBitStuff = 0x00; + return; + } // END if + + // The variable tncShift contains the lastest data byte. + // NRZI enocde the data stream. + if ((tncShift & 0x01) == 0x00) { + if (tncTxBit == 0) + tncTxBit = 1; + else + tncTxBit = 0; + } + + // Save the data stream so we can determine if bit stuffing is + // required on the next bit time. + tncBitStuff = ((tncBitStuff << 1) | (tncShift & 0x01)) & 0x1f; + + // If all the bits were shifted, get the next byte. + if (++tncBitCount == 8) + { + tncBitCount = 0; + + // If everything was sent, transmit closing flags. + if (++tncIndex == tncLength) + { + tncIndex = 0; + tncShift = 0x7e; + tncMode = TNC_TX_END; + } else + tncShift = tncBuffer[tncIndex]; + + } else + tncShift = tncShift >> 1; + + break; + + case TNC_TX_END: + // The variable tncShift contains the lastest data byte. + // NRZI enocde the data stream. + if ((tncShift & 0x01) == 0x00) { + if (tncTxBit == 0) + tncTxBit = 1; + else + tncTxBit = 0; + } + + // If all the bits were shifted, get the next one. + if (++tncBitCount == 8) + { + tncBitCount = 0; + tncShift = 0x7e; + + // Transmit two closing flags. + if (++tncIndex == 2) + { + tncMode = TNC_TX_READY; + + return; + } // END if + } else + tncShift = tncShift >> 1; + + break; + } // END switch +} + +/** + * Generate the plain text position packet. + */ +static int tncPositionPacket(void) +{ + int32_t latitude = ao_gps_data.latitude; + int32_t longitude = ao_gps_data.longitude; + int32_t altitude = ao_gps_data.altitude; + + uint16_t lat_deg; + uint16_t lon_deg; + uint16_t lat_min; + uint16_t lat_frac; + uint16_t lon_min; + uint16_t lon_frac; + + char lat_sign = 'N', lon_sign = 'E'; + + if (latitude < 0) { + lat_sign = 'S'; + latitude = -latitude; + } + + if (longitude < 0) { + lon_sign = 'W'; + longitude = -longitude; + } + + /* Round latitude and longitude by 0.005 minutes */ + latitude = latitude + 833; + if (latitude > 900000000) + latitude = 900000000; + longitude = longitude + 833; + if (longitude > 1800000000) + longitude = 1800000000; + + lat_deg = latitude / 10000000; + latitude -= lat_deg * 10000000; + latitude *= 60; + lat_min = latitude / 10000000; + latitude -= lat_min * 10000000; + lat_frac = latitude / 100000; + + lon_deg = longitude / 10000000; + longitude -= lon_deg * 10000000; + longitude *= 60; + lon_min = longitude / 10000000; + longitude -= lon_min * 10000000; + lon_frac = longitude / 100000; + + if (altitude < 0) + altitude = 0; + + altitude = (altitude * (int32_t) 10000 + (3048/2)) / (int32_t) 3048; + + return sprintf ((char *) tncBuffer, "=%02u%02u.%02u%c\\%03u%02u.%02u%cO /A=%06u\015", + lat_deg, lat_min, lat_frac, lat_sign, + lon_deg, lon_min, lon_frac, lon_sign, + altitude); +} + +static int16_t +tncFill(uint8_t *buf, int16_t len) +{ + int16_t l = 0; + uint8_t b; + uint8_t bit; + + while (tncMode != TNC_TX_READY && l < len) { + b = 0; + for (bit = 0; bit < 8; bit++) { + b = b << 1 | (timeNCO >> 15); + timeNCO += timeNCOFreq; + } + *buf++ = b; + l++; + tnc1200TimerTick(); + } + if (tncMode == TNC_TX_READY) + l = -l; + return l; +} + +/** + * Prepare an AX.25 data packet. Each time this method is called, it automatically + * rotates through 1 of 3 messages. + * + * @param dataMode enumerated type that specifies 1200bps A-FSK or 9600bps FSK + */ +void ao_aprs_send(void) +{ + uint16_t crc; + + timeInit(); + tncInit(); + tncSetCallsign(); + + tncLength = tncPositionPacket(); + + // Calculate the CRC for the header and message. + crc = sysCRC16(TNC_AX25_HEADER, sizeof(TNC_AX25_HEADER), 0xffff); + crc = sysCRC16(tncBuffer, tncLength, crc ^ 0xffff); + + // Save the CRC in the message. + tncBuffer[tncLength++] = crc & 0xff; + tncBuffer[tncLength++] = (crc >> 8) & 0xff; + + // Prepare the variables that are used in the real-time clock interrupt. + tncBitCount = 0; + tncShift = 0x7e; + tncTxBit = 0; + tncIndex = 0; + tncMode = TNC_TX_SYNC; + + ao_radio_send_aprs(tncFill); +} + +/** @} */ |