Parts, PCBs, and Stencils arrived earlier this week so I put together the three prototypes for REV4. Above is pre reflow.
Directly after reflow.
Magnified picture of the board. Turned out great. FTDI chip flashes and Propeller programs over USB. The new MAX11613 ADC works as well. I will be posting the driver code for that shortly.
Some changes from REV 3 to REV 4.
Micro SD Card Slot changed. Old one was Molex MFG# 502570-0893. New part is 4UCON MFG# 15882.
Tact Switch changed to more low profile switch.
ADC switched from AD7999YRJZ-1500RL7 to MAX11613EUA+. Slower ADC but increase from 8bit to 12bit resolution.
Changed Voltage Regulator from TS2937CW33 to NCP1117LPST33T3G.
Added 10uF Electrolytic Cap to 3.3V rail.
Crystal changed to low profile ABMM-6.000MHZ-B2-T.
Added voltage divider to switch to USB power if external power falls near cutoff for regulator.
Render of the PCB from OSHPark.
Top stencil pattern. The through hole pads on the micro USB connector are going to be soldered with the “Paste In Hole” method. I have not tried this yet but if it works I will be able to cut out an entire operation during production of the boards.
Finished the next revision of the Propeller Development Stick REDUX. The power switching has been changed to fix the flakiness of the past revision. I switched the TPS2115 to a TPS2113. This seems to have fixed the weird power switching issues. The layout has change completely. SD card slot is on the top side of the board and the power circuity and ADC are on the bottom now.
These are the test v-score panels. I also have a tabbed version of the panel in the fab for further testing.
Finished placing the PDS into a 12″x6″ panel that produces 20 individual boards.
Just finished the documentation for the PDS REV 2. You can find the complete documentation on my github repository. Working on Panelizing the board for assembly and the Kickstarter video.
The Prop Dev Stick gets a quick review and demo by the Tymkrs!
Big thanks to them for helping me get the word out about the board.
Follow the Tymrks on twitter: @tymkrs
I have the first 5 Prop Dev Sticks boxed up for testers. I will be dropping them off at the post office tomorrow. Hopefully no hardware bugs pop up!
Also I am looking into adding more daily blogs posts. Content like app-notes, engineering design thoughts, and interesting parts.
I updated the PDS repository with information on how to configure the FT230X EEPROM and the Propeller Tool IDE.
Template for FT230X EEPROM
You will need to download FT-Prog from FTDI. The FT230X needs to be flashed with this template for the Propeller Development Stick to function correctly.
Also the Propeller Tool needs a tweak to its options to make it use the RTS signal to reset the Propeller instead of the DTR signal (which the FT230X does not have). Do this by opening Propeller Tool and clicking Edit. At the bottom there is “Preferences”. Under the tab “Operation” there will be Propeller Reset Signal. Change it from “DTR” to “DTR & RTS”. Press accept to save the settings. Propeller GCC using SimpleIDE also allows you to change the reset signal in the general tab of properties.
The Propeller Development Stick (PDS or Prop Dev Stick for short) is a simple development board for the Parallax Propeller Microcontroller. I already had an older design but I wanted to expand the usefulness of the platform. The Redux version throws out the old version completely and starts over from scratch.
The new PDS features a ADC and a micro SD card slot for storage. Also the speed of the Propeller gets a 16MHz speed bump (from 80MHz to 96Mhz) with the addition of a 6Mhz crystal. Form factor is improved by slimming down the design which enables it to fit on a breadboard. The old USB male plug is gone and it now uses a standard micro USB. This way the user can embedded the device and still program or pull data off of it.
It fully complies with the USB standard. The device uses the FT230X USB to Serial chip and waits to turn on the power buss in till the PC gives the device permission to pull power. This is done by a p-channel mosfet. To switch from USB power to external power (like a battery) a power mux is used. The mux has built in current limiting which is set to 500mA.
Last night I soldered the new REV 1 board. Everything is working correctly and the footprints/silkscreen are also correct. Will be working on the page documenting the progress of the PDS. Will also upload the design files.
Progression from the first PDS on the left to the newest one on the right. Slightly longer but slightly thinner now. Changed the USB port to a micro usb port. Added an ADC and mirco SD card slot.
Layout of the PCB.