I've been cooking up a new Platform Module - this is the Propeller Platform SD. First the basics;
- 2.8" x 2.5"
- Compatible with all other Platform Modules (DMX IO, LCD UI, ProtoPlus, El Jugador, OctoDriver, PropNet, Prototyper, Tester, Battery, etc).
- Will come 100% pre-assembled and tested.
- Includes 512kb EEPROM, 5Mhz socketed crystal, and uSD card slot
- Super low dropout regulators- although I put 7V on the pcb, they'll run within 100mV of the output voltage, so 5.1v input minimum.
- Comes with a special bootloader so you will be able to program a Prop without a Programming stick!
I've attached a picture of a prototype I've been testing for the past few weeks. I put it together by hand so it's a little grungy, but the final versions will go to an assembler (You can see the fiducials in the photo).
The part I'm most excited about is actually the software - the Prop Platform SD will come with a special bootloader so you can program without a PropPlug. This way, you can update your program in the field, without a computer. You can also easily switch programs by swapping memory cards. Programming with a PropPlug / Clip is still an option and headers are on the board. Once your program is running, it can access the SD card like normal, so it's great for doing stuff like datalogging, menus, etc.
I've been testing it for a while, and there are enough 'little things' that I want to change, I've decided to re-rev the design. I thought I'd ask for feedback to see what else should be changed / added / removed.
Also, a few specific questions:
- Does anyone use a USB2SER adapter? The Propeller Platform has connections for it, not sure if I should keep it on.
- The bootloader will work by looking for files on the uSD card. If there's a 'run.bin' on the uSD, the Prop will start executing it. If there's a load.bin, it will load that file into the upper half of the EEPROM. If nothing is found, it will load the upper half of the eeprom. If there's a load.bin AND a run.bin on the uSD card, which should the bootloader update the EEPROM or execute run.bin?
For Rev. B, I was going to fix the uSD jumpers, add more vias under the vregs, change the silkscreen to reflect min. voltage of 5.5v, and use a different uSD slot (everyone has problems assembling the 3M slot). Any other suggestions for a re-rev? Would a Propeller Platform with a built-in SD card reader and bootloader be useful?
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