pedward: Just be careful not to assemble too many until you know the demand. I would not like for you to put all you $$s into a project until you knw it is going to succeed. At least if you have unassembled parts you can use them on another project.
Oh, for certain I'm aware of that folly. I'm going to order the min quantity of medium run boards (150 sqin) via DbPDX, which should be around 65-70. I'll make 10 or 20 to start, then it's just a matter of ordering more components.
pedward: Have you sent your final pcb out for production yet? Now that I can see the assembled board in the flesh perhaps I can offer some suggestions.
Looking at your design I am wondering if it would be possible to place your more difficult smt parts (prop, ftdi, uSD connector) on the one side of your pcb, with the other jellybean parts on the other.
You can save space by using resnets for the 10K resistors (try digikey CR6S8xxxx) - they are 0603 style in a 1206 package. Use longer smt pads to make the soldering easier.
You can reduce the parts by one by using a sot23 transistor with inbuilt 10K BE resistor with either a series 470R or 1K into the base - saves the BE resistor.
I have not used a reset sw on any of my designs. Is this important??
I note you are using the 3v3 from the ftdi. With a prop and microSD you are likely on the limit of what the ftdi can supply. Have you considered putting an optional 3v3 sot23 regulator on the pcb? Your 10uF cap will be required on the input and another on the output. You can use via's .020" to make the links to minimise space.
These are just some ideas that may interest you. Try and put a gnd and a power plane under the prop if possible.
Question, I'm working on the final board layout for the prototype memory daughter board for the PropKey. This is a board which is intended to mount on the bottom side of the PropKey and provide 512KB (or 256KB) of SPI SRAM (8 bits wide) and 16MB of SPI flash (8 bits wide). I was thinking of putting a VGA connector on the end of this board. Does anyone think this would be neat, or a feature that really isn't useful? Perhaps a separate board, with VGA and other peripheral connectors would be more useful.
I intended the board to be used primarily for development, but anything is possible, I don't know how others may use it.
Question, I'm working on the final board layout for the prototype memory daughter board for the PropKey. This is a board which is intended to mount on the bottom side of the PropKey and provide 512KB (or 256KB) of SPI SRAM (8 bits wide) and 16MB of SPI flash (8 bits wide). I was thinking of putting a VGA connector on the end of this board. Does anyone think this would be neat, or a feature that really isn't useful? Perhaps a separate board, with VGA and other peripheral connectors would be more useful.
I intended the board to be used primarily for development, but anything is possible, I don't know how others may use it.
Maybe Ken can use it for "PropellerPoint" Presentations ...
Rayman has already demonstrated some good graphics reading from SST26VF parts.
Winbond parts and SPI-SRAM would probably be too slow for video setup times.
Not if the video is on the same pins as the I/O. But then it would be a bunch of garbage during other times. With VGA at 25Mhz, you could make it work if you did 320x240 actual pixels, but 640x480 is too fast. Those SPI parts are around 66Mhz, so that isn't the choke point. If you had 2 COGs reading data, you could get 40MB/s from the SPI.
I put a medium run order of PropKEY boards on order, 80 to be exact. I don't know when they will show up, but they have been ordered. I'll post more once I've got details.
Yay!! I need one because my coworkers at my day job are starting to wonder about the strange little boxes and boards I plug into my work computer while I sit at my desk....must be some sort of corporate terrorist!!
Hey, would anyone be interested in one of these as a kit? I have all of the SMD components on hand, reels of them. I could put together kits or sell bare boards, I figure most people would want a finished board or a kit, not a bare PCB. I am also thinking of adding a micro SD socket to the board, Molex has a very compact socket that would be easier to add.
The Prop is a .8mm pitch and the FT232RL is .65mm pitch, the passives are SOT-23, 0603, 0805, and 1208. The reset button is a nice tactile momentary PTH device. The soldering does present a challenge, but not a huge challenge.
EDIT: removed shots and put new ones at top.
I'm down for a kit. This would be super handy for portable testing and prototyping
I put a medium run order of PropKEY boards on order, 80 to be exact. I don't know when they will show up, but they have been ordered. I'll post more once I've got details.
How is the "toy" coming along? Do you have any yet? I could do with one or two.
Comments
You can save space by using resnets for the 10K resistors (try digikey CR6S8xxxx) - they are 0603 style in a 1206 package. Use longer smt pads to make the soldering easier.
You can reduce the parts by one by using a sot23 transistor with inbuilt 10K BE resistor with either a series 470R or 1K into the base - saves the BE resistor.
I have not used a reset sw on any of my designs. Is this important??
I note you are using the 3v3 from the ftdi. With a prop and microSD you are likely on the limit of what the ftdi can supply. Have you considered putting an optional 3v3 sot23 regulator on the pcb? Your 10uF cap will be required on the input and another on the output. You can use via's .020" to make the links to minimise space.
These are just some ideas that may interest you. Try and put a gnd and a power plane under the prop if possible.
I intended the board to be used primarily for development, but anything is possible, I don't know how others may use it.
Maybe Ken can use it for "PropellerPoint" Presentations ...
Rayman has already demonstrated some good graphics reading from SST26VF parts.
Winbond parts and SPI-SRAM would probably be too slow for video setup times.
I'm down for a kit. This would be super handy for portable testing and prototyping