From: Bdale Garbee Date: Thu, 25 Aug 2011 05:51:38 +0000 (-0600) Subject: Merge branch 'master' of ssh://git.gag.com/scm/git/fw/altos X-Git-Tag: 1.0~11 X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=242344d3e32e7c7cd9270d708555923fa888e4d8 Merge branch 'master' of ssh://git.gag.com/scm/git/fw/altos Conflicts: doc/altusmetrum.xsl --- 242344d3e32e7c7cd9270d708555923fa888e4d8 diff --cc doc/altusmetrum.xsl index 2a02421b,1b1f76a4..c8ffedac --- a/doc/altusmetrum.xsl +++ b/doc/altusmetrum.xsl @@@ -601,13 -582,82 +582,8 @@@ NAR #88757, TRA #1220 than the primary so that both pyrotechnic charges don't fire simultaneously. - - To set the main deployment altitude, use the 'c m' command. - As with all 'c' sub-commands, follow this with a 'c w' to write the - change to the parameter block in the on-board DataFlash chip. - -
- Calibration - - There are only two calibrations required for a TeleMetrum board, and - only one for TeleDongle and TeleMini. - -
- Radio Frequency - - The radio frequency is synthesized from a clock based on the 48 MHz - crystal on the board. The actual frequency of this oscillator must be - measured to generate a calibration constant. While our GFSK modulation - bandwidth is wide enough to allow boards to communicate even when - their oscillators are not on exactly the same frequency, performance - is best when they are closely matched. - Radio frequency calibration requires a calibrated frequency counter. - Fortunately, once set, the variation in frequency due to aging and - temperature changes is small enough that re-calibration by customers - should generally not be required. - - - When the radio calibration value is changed, the radio - frequency value is reset to the same value, so you'll need - to recompute and reset the radio frequency value using the - new radio calibration value. - -
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- TeleMetrum Accelerometer - - The TeleMetrum accelerometer we use has its own 5 volt power supply and - the output must be passed through a resistive voltage divider to match - the input of our 3.3 volt ADC. This means that unlike the barometric - sensor, the output of the acceleration sensor is not ratio-metric to - the ADC converter, and calibration is required. We also support the - use of any of several accelerometers from a Freescale family that - includes at least +/- 40g, 50g, 100g, and 200g parts. Using gravity, - a simple 2-point calibration yields acceptable results capturing both - the different sensitivities and ranges of the different accelerometer - parts and any variation in power supply voltages or resistor values - in the divider network. - - - To calibrate the acceleration sensor, use the 'c a 0' command. You - will be prompted to orient the board vertically with the UHF antenna - up and press a key, then to orient the board vertically with the - UHF antenna down and press a key. - As with all 'c' sub-commands, follow this with a 'c w' to write the - change to the parameter block in the on-board DataFlash chip. - - - The +1g and -1g calibration points are included in each telemetry - frame and are part of the header extracted by ao-dumplog after flight. - Note that we always store and return raw ADC samples for each - sensor... nothing is permanently "lost" or "damaged" if the - calibration is poor. - - - In the unlikely event an accel cal that goes badly, it is possible - that TeleMetrum may always come up in 'pad mode' and as such not be - listening to either the USB or radio link. If that happens, - there is a special hook in the firmware to force the board back - in to 'idle mode' so you can re-do the cal. To use this hook, you - just need to ground the SPI clock pin at power-on. This pin is - available as pin 2 on the 8-pin companion connector, and pin 1 is - ground. So either carefully install a fine-gauge wire jumper - between the two pins closest to the index hole end of the 8-pin - connector, or plug in the programming cable to the 8-pin connector - and use a small screwdriver or similar to short the two pins closest - to the index post on the 4-pin end of the programming cable, and - power up the board. It should come up in 'idle mode' (two beeps). - -
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