Thanks Keith, this helps a ton! It’s great to hear that those pins are exposed & there aren’t any giant road blocks. The EEPROM logging would definitely be nice, but the lat/long telemetry is priority 1.
I’ll start digging through the code once I hit go on a TeleMini order & get it in. Thanks! -Bryan > On Sep 3, 2017, at 9:44 PM, Keith Packard <[email protected]> wrote: > > Bryan Duke <[email protected]> writes: > >> Hi everybody. I posted on the Facebook group, but someone there suggested I >> try the mailing list instead… >> >> I’m putting a TeleMini in a nosecone for a 24mm rocket that I’m hoping >> to break the TRA G-motor record with. There isn’t enough room in the >> nosecone for anything bigger than the TeleMini, but it looks like >> there will be just enough room for a separate little GPS. Is there a >> way to feed the TeleMini a NMEA stream & have it send GPS coordinates >> over its telemetry? It looks like several of the STM32's pins are >> accessible....I'm ok writing some code to make it happen. > > This should be reasonably straightforward. TeleMini has a 6-pin > connector. Four of those are our standard debug connector (debug > data/clock, reset and ground). The other two are normally a regular USB > connection. You can hook those to a USB cable. However, those same two > pins can be re-configured to talk to a serial device, such as a GPS > device. > > Pin 1 is TX > Pin 2 is RX > Pin 3 is gnd, and the pad around that is square. > 4,5,6 are the debug connectors. > > The source code for AltOS has GPS drivers for u-blox, sirf and skytraq > already available, and the radio driver has all of the necessary > bits to send our regular digital telemetry as well as APRS. > > So, if you're up for building the firmware, what I'd suggest is: > > 1) Leave the USB running for a while when the device boots. This will > make reflashing a ton easier as the alternative is to reflash over > the debug link, which is really slow. > > 2) After 'a while' (maybe 10-20 seconds?), turn off the USB and then > reconfigure the pins to talk to the GPS device. > > Normally, we log GPS data to the eeprom, so eventually you'll want to > add that, but it's a bit of work. Doing the GPS telemetry is quite easy > though, along with making APRS work. > > There are 33ohm resistors on the board for the USB port; I don't think > those will hurt communication with the GPS chip, but you should be aware > that they are present. > > -- > -keith _______________________________________________ altusmetrum mailing list [email protected] http://lists.gag.com/mailman/listinfo/altusmetrum
