Project Logs

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• RX/TX

  Shane Burrell • 05/28/2015 at 11:48 • 0 comments

  I've been doing some testing receiving and transmitting 4FSK packets. Phase noise limits output to about 3 watts. This could be reduced by using an external VCO design and different ADF IC.

• Firmware Load

  Shane Burrell • 04/16/2015 at 03:02 • 0 comments

  Slow steady progress on board turn up and assembly. All three power rails are up. STM programmed and talking to the transceiver.

• Reflow of first Board.

  Shane Burrell • 04/10/2015 at 00:12 • 0 comments

  Reflowed rev of the complete compact design. Went well other than skewing the USB connector.

• Board Arrival and Prep.

  Shane Burrell • 04/09/2015 at 00:05 • 0 comments

  Boards arrived.

  OSC1 traces were cut and prepped for connection to OSC2 after reflow. Had to add the holes for Tag Connect. Kicad option was turned off for non plated holes so drill hits weren't made.

  Setup stencil and last few checks of reflow oven profile.

• OLED Driver Progress, STM32 I2C woes.

  Shane Burrell • 04/04/2015 at 01:37 • 3 comments

  I've spent several hours the last few nights trying to figure out why output wasn't working. First I assumed it was an upgrade to Cube 1.5 which is a fairly safe bet, as the HAL drivers are a buggy abstraction layer as to what is actually going on. Then it finally came to me that the proto board had pullups and the Discovery board did not. I enabled the internal pullups and bingo it was working as it should. OLED driver for the SSD1306 is now working along with fonts and mono bitmaps. I've also improved my ADF init strategy which should now support fine cal mode. Hopefully new proto boards will be in late next week. More good news the VHF PA footprint/package can be had in a UHF version which I've ordered samples. Other than a few passives and finding a replacement Tx/Rx switch it should be trivial to have a vhf version and uhf version.

• Simulation, Testing, Firmware.

  Shane Burrell • 04/02/2015 at 00:50 • 0 comments

  Big strides tonight getting all (including rarely used) sections of the ADF driver working all in a nice format and verified with test board / peek at logic . Phase noise from the datasheet was a concern however simulation and testing so far it doesn't seem to be with external PA and ramp requirements. I don't plan to drive up the full PA level and everything looks good for up to 4 watts output. Made minor change to gerbers for next board spin. Swapped OSC1 and OSC2. OSC2 will do CMOS level tcxo. OSC1 will not requires .8v peak to peak. CMOS parts are easier to come by. Verified with ADF module switching between GMSK and 4FSK. Refactored ADF driver to later support UHF band optionally.

• Stencil Arrival. More work on firmware.

  Shane Burrell • 04/01/2015 at 00:02 • 0 comments

  Stencils arrived today. Waiting on boards. More work on the firmware. Upgraded STM HAL to new version 1.5 and backported my changed to the HAL. These abstraction layers never work exactly the way you need them to so modifications are usually necessary. Should be ready to place and reflow when boards arrive.

• More ADF-7021-N Driver work.

  Shane Burrell • 03/29/2015 at 23:21 • 1 comment

  A bit more work adding cal to driver.

• More Firmware work. GPS/OLED mockup.

  Shane Burrell • 03/28/2015 at 23:13 • 0 comments

  Added support for spi flash . Bit more mockup on oled display and gps.

• Firmware Progress...

  Shane Burrell • 03/28/2015 at 01:09 • 0 comments

  The first build of firmware is done and only minor tweeks should be needed. Tested with a STM32F4Discovery board. The driver for the ADF7021-N should be complete and verification via logic analyzer indicates it should bring up the transceiver and go into RX mode. I've added a PTT input definition to one of the many extra pins. Pressing the PTT will transmitted "Hello World" in the first frame and a AMBE audio snippet afterwards saying "Hello World". The OLED display works great even for its very small size. Bright and easy to read low power budget. The Neo GPS module I've used before and I have embedded its output in the last data frame thats sent. Made some small modifications to the new STM CUBE library as it never quite works the way you want it to.

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