This documentation covers few different hardware revisions. Each secion which is specific to certain Hw Rev is marked by a letter. If section or point is universal across all revision it doesn't have any explicit marking. 1. INTRODUCTION ParaTNC is not only a software which runs on the STM32VLDISCOVERY board. Let's be honest, using evaluation boards is not very professional and may lead to great mess with soldering, poor-quality universal PCBs and then short circuits, noise etc. This is why the ParaTNC hardware was designed to have everything on single PCB without a lot of jumper wires across. The ParaTNC as a software is universal and it might by used both on ParaTNC hardware and still on STM32VLDISCOVERY board with everything else connected to it using kynar wire. 2. KEY FEATURES There were few key assumptions during the designing process which came from long experience with many different stations -> Ground Isolation between the controller and the radio. -> Ground Isolation and isolated power supply for external meteo sensors. -> RS232 and optional RS485 transceivers on board. -> Internal connectors for breakout board with MS5611 pressure sensor. -> Separate watchdog IC. -> Optional Radiometrix BiM1H 500mW VHF transceiver tuned on 144.800MHz. -> The PCB mechanical design which fits into standard Mikrotik RB411 case. -> Supplied from single +12V...14V5 DC source using standard DC barrel jack. The main problem observed during long experience with meteo stations is RF feedback. Most sensors (like temperature, wind and humidity) needs to be placed outside to ensure proper measuremenets quality. Unfortunately extending micro GPIO pins directly by using long cables placed along with the RF coax cabling, definitely allows the RF energy from stations own TX to get inside the micro and do a lot of mess. In less dangerous case this may end with distorted AF coming into modulator input, in the worst case the micro could just hang with PTT engaged. 3. SERIAL BOOTLOADER The PCB has a JTAG pinout exposed which may be used for downloading the software into micro. If User don't want to use a JTAG programmer or he just doesn't own one, the serial bootloader may be used. The bootloader is activated by shorting the proper jumper and reseting the controler. Then the application provided by STMicroelectronics could be used to download the HEX file into the micro. 4. CONNECTORS PINOUT (BACK EDGE) - HW-RevA ------------------------------------------------------------------------------- |RS485B , RS485A| |+5Vsw, OneWire, AGND| |TX20, AGND, +5Vsw, DTR| \r\n |+12V, +5V, +5Vi, +3V3, AGND, GND| Where: RS485A and RS485B -> RS485 bus, protected by TVS (Clamping diodes) OneWire -> Isolated one wire bus TX20 -> Isolated data bus from LaCrosse TX20 anemometer DTR -> Enable pin for TX20 anemometer. Permamently pulled down do AGND +5Vi -> Isolated +5V generated by internal DC-DC converter +5Vsw -> Switched and Isolated +5V. This line could be power cycled by the micro if no communication will be received from either the anemometer or one wire thermometer +3V3 -> Main uC supply voltage regulated internally by LDO +12V -> Main supply voltage, hooked in paralel to DC jack AGND -> Analog GND for radio and sensors GND -> Main ParaTNC common with DC jack 4. CONNECTORS PINOUT (BACK EDGE) - HW-RevB ------------------------------------------------------------------------------- |RS485B , RS485A| |+12V, AGND, +5Vi, +5Vsw, +5V, GND| |+5Vsw, OneWire, AGND| |AGND, TX20-SPD, DIRECTION, +5Vsw| Where: RS485A and RS485B -> RS485 bus, protected by TVS (Clamping diodes) OneWire -> Isolated one wire bus TX20-SPD -> Isolated data bus from LaCrosse TX20 anemometer or an windspeed input (pulse out) from mechanical anemometer DIRECTION -> Wind direction input (pot wiper) from mechanical anemometer DTR -> Enable pin for TX20 anemometer. Permamently pulled down do AGND +5Vi -> Isolated +5V generated by internal DC-DC converter +5Vsw -> Switched and Isolated +5V. This line could be power cycled by the micro if no communication will be received from either the anemometer or one wire thermometer +12V -> Main supply voltage, hooked in paralel to DC jack AGND -> Analog GND for radio and sensors GND -> Main ParaTNC common with DC jack 4. CONNECTORS PINOUT (BACK EDGE) - HW-RevC ------------------------------------------------------------------------------- |+12V, AGND, +5Vi, +5sw, OC-OUT, GND| |RS485B , RS485A| |+5Vsw, OneWire, AGND| |AGND, TX20-SPD, DIRECTION, +5Vsw| Where: RS485A and RS485B -> RS485 bus, protected by TVS (Clamping diodes) OneWire -> Isolated one wire bus TX20-SPD -> Isolated data bus from LaCrosse TX20 anemometer or an windspeed input (pulse out) from mechanical anemometer DIRECTION -> Wind direction input (pot wiper) from mechanical anemometer +5Vi -> Isolated +5V generated by internal DC-DC converter +5Vsw -> Switched and Isolated +5V. This line could be power cycled by the micro if no communication will be received from either the anemometer or one wire thermometer OC-OUT -> Additional isolated open-collector output +12V -> Main supply voltage, hooked in paralel to DC jack AGND -> Analog GND for sensors (BUT NOT RADIO!!) GND -> Main ParaTNC common with DC jack 5. RJ45 (RS232) pinout The RJ45 jack on the front of the PCB is NOT THE ETHERNET! Please don't plug any twisted pair Ethernet cable onto it. The RJ45 socket is just an RS232 connector in standard Cisco Serial Console pinout. The proper RJ45 -> DB9 cable could be very easly obtain on any online shop like eBay etc. The only difference between official Cisco pinout and ParaTNC is an optional (disabled by default) +5V voltage which may by applied to pin 7 of RJ45 connector, which is wired to pin 4 of female DB9 plug. 6. Female DB9 (radio) pinout The DB9 connector is used to connect to the radio used for receiving & txing data on the APRS radio network. As mentioned before this connector has a ground separation and it is isolated from the microcontroller using AF transformer and optocoupler (for PTT). An input transformer has a 220uF 16V electrolytic capaciter in series between a primary winding and DB9. The positve lead faces the DB9 connector to isolate potential DC offset coming from the radio. The connector itself repeats the Tapr (Muel) TNC-2 pinout which goes as below: Pin 3 - AF from Radio to TNC Pin 4 - Open Drain PTT Pin 5 - AF from TNC to Radio Pin 7 - AGND 7. Adjusting audio levels The ParaTNC controller has two trimpots mounted on PCB which may be used to tune the level of audio coming from/to the radio. The trimpot located close to the microcontroller is used to set the output signal level. The another one which is near right isolation transformer changes the input level and it is hooked up between the primary winding and DC-blocking electrolytic 8. JUMPERS (Sketch not to scale!) ------------------------------------------------------------------------------- | | | JP1 MS5611 sensor | | x ----------- x | | x |JTAG conn| x | | ----------- x | | x | | /----------\ x | | | | x | | | MICRO | DHT22 sensor x | | | | x | | \----------/ x | | x | | RS232 sel | | >xx< | | >xx< | | | | JP3 | | x | | x -------------- | | | RS232 conn | | | -------------- | ------------------------------------------------------------------------------- JP1 - This is used to jump to the serial bootloader during startup JP3 - This is used to apply regulated +5V supply to RS232 connector RS232sel - This pair of jumpers is used to choose RS232, present only in HW-RevA MS5611 - .1' Connector for GY-63 breakout board with MS5611 pressure sensor ========= | empty | | empty | | empty | | SDA | | SCL | | GND | | +5V | ========= DHT22 - .1' connector for DHT22 humidity sensor ========== | +5V | | Sensor | | GND | ========== 9. CHOOSING BETWEEN RS485 AND RS232 (applies only to HW Revision A) ParaTNC controller has connectors for both 485 and 232 variant of RS standard. This doesn't automatically means that ParaTNC has two separate serial ports, this is still the same serial port from the microcontroller which just may be converted differently. Due to how TTL and CMOS logic works You CANNOT use both 232 and 485 at once. If You'll leave 485 and 232 enabled at once the main logic supply voltage may be shorted to ground if one transceiver will receive logic one while the another will receive zero (and pull low the TTL/CMOS rx line which goes to the micro) It is strongly recommended to put MAX485 into socket. In such case the transition from RS485 to RS232 could be done just by removing MAX485 from the socket and then shorting the RS232sel jumpers block. Jumpers needs to be shorted horizontally