http://uavdevboard.googlegroups.com/web/Nav.JPG?gsc=RKYj6wsAAABmbYecSmDzk5iutmreN8VJThe Nav board has the dsPIC33FJ256GP710A and all of the following:1) 8 PWM / PPM inputs connected by rc servo style connectors.2) 8 PWM / PPM outputs connected by rc servo style connectors - this power is separated from the rest of the board.3) 4 extra rc servo style connectors connected to 3.3v i/o pins that can be analog inputs, timer clocks (read tachometer inputs) or general purpose inputs or outputs. Two of these provide the power connection to the servo's.4) An 8 pin .1 spacing header giving logic side connection to a CAN transceiver and the CAN buss, including full, half or no termination. Ground and 5v power provided.5) An 8 pin .1 spacing header power interface header - meant to go to power board mentioned below but can be used other ways with two analog inputs were the power board provides voltage and current.6) 6 pin JST connector for GPS with voltage select pads for 3.3v and 5v power and pads for pull up resistor.7) 6 pin JST connector for second serial, including RTS / CTS with voltage select pads for 3.3v and 5v power.8) 6 pin JST connector to I2C2, provides 3.3v and 5v power and a pin to termination resistors.9) 6 pin JST connector to SPI1, provides 3.3v power and slave signal select.10) 6 pin JST connector to SPI2, provides 3.3v power and slave signal select, shared by on board 24 bit A/D used on pressure sensors (SS would need an inverter on it if the A/D is present on the board).11) 6 pin JST connector with 3.3v analog power and 4 analog inputs.12) Pads for Hirose connector matching the one used on the PIC32 dev kits, with the CAN signals brought to the logic side interface.13) Normal 6 pin ISCP + 1 header, with GPIO on the unused 6th and extra 7th pin that's meant to go to power board and can be cut off to use all existing ISCP adapters / cables etc.14) Reset push button, 4 status LED's.15) Layout for two Inversense IXZ500 gyro's, spi interface to AD7793 24 bit a/d connected to two Freescale pressure inputs (speed and altitude), I2C interface to ST's integrated accelerometer / magnetometer or AD / Honywell separate function parts, I2C interface EEPROM, 3.3v digital side regulator, low noise 3.3v analog regulator, low noise 1.8v regulator, clock source.http://uavdevboard.googlegroups.com/web/Power.JPG?gsc=RKYj6wsAAABmbYecSmDzk5iutmreN8VJThe Power board has the following:1) Input power connectors, both standard rc 3 pin and Deans 4 pin (highly recommended), meant for 2s LiPo, reverse polarity protected.2) External servo power input, both standard rc 3 pin and Deans 4 pin (highly recommended).3) Jumper link selection of servo power source, completely (other than ground) isolate servo power.4) Headers to match up with 1 to 5 and 13 mentioned above, this board is meant to stack directly on top of the Nav board.5) Layout for 3A rated 5v output regulator as input power for Nav board.6) Layout for two 3A rated 5.5v output load sharing servo power regulators, good for 8 standard servos.7) Resistor divider network and INA for total board current analog outputs.We did consider SMPS instead of regulator's but for 2 cell input the dissipation isn't that much better and the noise is terrible. In actual use you may be able to get away with 3 cell input using less and / or smaller servo's. The regulator's are all reverse voltage protected.If you have a look at the pictures I uploaded you can see there is lots of space available on the power board, hens the question of what would we like to see there. To clarify, the on board programming would be by USB, and connect exactly as a PicKit2 does as it would use the same chip and firmware as what is in the PickKit2. Additional serial ports and / or the SD card access would be over CAN buss running on another pic or perhaps a simpler interface using the extra pins on the ICSP header. It may even be possible to do the SD card and programming in the same pic, but clearly not at the same time. It seems strange to add all these processors but you need to remember its a chip that costs less than $5 and does not have to be there, at this point its really about using the space of the board as it make no difference to the cost.
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Everything anyone could want seems to be in there. It may be an unfounded concern, but with the mags being where they are...make sure there isn't any ground plane or components with nickel in their terminations too close, also hard to say what affects the high currents of the power board will do to the fields regarding mag...
I hate wires..the more integrated the better..you guys are doing a great job in that respect..keep up the good work.
Empty space....Mediatek GPS module .....or.....put the mag sensors there away from things and ground planes.
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I hate wires..the more integrated the better..you guys are doing a great job in that respect..keep up the good work.
Empty space....Mediatek GPS module .....or.....put the mag sensors there away from things and ground planes.