Jim as you suggested, I opened up a thread for this.
For a while I wondered about building a Basic Atom Pro 40 board with the Lynxmotion form factor and I even did a quick and dirty layout of it. But thinking about it I figured that it does not make sense cost wise. That is assuming that I could buy one for the price of the BB2, the cost would be: $25+$75=$100 and the Arc32 is $100,
But I wonder about building a board for: basicmicro.com/BasicATOM-Pro … _p_93.html
At a price of: $13 for the actual processor that is used in Bap40/Arc32, it has about 50 IO pins (16 of which are analog), It has the other benefits like the Arc32, of faster speed, more memory, … Would take about the same number of support chips as the Arduino board, maybe a little more for the EEPROM, could choose to do USB or not, could choose to put in the powered by USB or not…
I have done a quick and dirty 3x2.3 layout of a board with this chip using Dip Trace. Not saying that this is perfect but at least it is good enough to start a conversation. The current design has:
20 digital pins on bottom (with 3 servo type connectors, can choose VS/+5v)
12 digital pins on top (like above)
4 pin connector for UART2 (TX, RX, GND, +5v)
8 Analog pins – Note: these were all just lumped at top with no power/ground pins. With this chip they have their own P number and are input only…
Speaker hard wired to a specific IO pin (P52)
3 Buttons - also hard wired
3 LEDS - ditto.
A jumper that add PU resistors to I think P16 and P19 - For PS2
If this is a thing of interest, there are several trade offs/changes we should consider, things like:
Maybe drop 4 digital pin (could add simple connections for these and that would probably leave room for the 8 analog pins with 3 pin headers…
I think I am pretty close right now to the FTDI hookup the BM has in their drawings that does not support power from USB bus. Maybe better to design with Arduino like USB that maybe has jumpers to allow you to configure for USB power.
Again I know that this still needs work and personally think that if we do go forward, that we probably wait until we make it at least one iteration of the Arduino and/or Prop boards to know what issues come up and not repeat the same problems.
Looks good Kurt! Mikes working on adding USB to the SSC-32 so we can share what works and what doesn’t from that build. This is a great start to a pretty cool idea.
FYI - I know that the Pattern I used on the TQFP in the above drawing is incorrect. I wondered as it did not look right. Sure enough it was not (The pattern above had 20 pins on one side then 12, 20, 12), instead of 16, 16, 16, 16. Also the real pattern it is quite a bit smaller, so I need to change the layout. I will probably change several things and end up with:
Keep the 20 digital pins at bottom.
Maybe cut down to 8 digital pins on top (3 pin headers)
Have the 8 analog pins on top with 3 pin headers - maybe hardwire these to 5v (or not)
3 LEDS/Buttons, will probably keep them on Top, but move them toward the right edge or maybe shift to right side. Also choose IO pins that are easy to route. L
Maybe move USB to left edge instead of right (along with FTDI and support),
Place reset button, where it can be used and try to minimize the Reset line…
Will try to expose any other digital IO lines that I don’t use as single pins… (never can have too many…)
Not sure about what Power options (have regulator/cap like old BB2 or like I changed to in Arduino board? ) Support USB power? Will be great to see what Mike comes up with.
Let me know if you have any other suggestions? I will be doing this at a background pace.
Kurt
P.S. - The Arduino boards/Parts should arrive here Monday.
It looks very interesting! May I ask why you “only” want 8 and not 16 analog ports?
Hardwired to 5v would save some pin. Do you also plan to have one analog wired to VL (1/4).?
I’m glad you got the speaker included.
Have you considered a XBee holder on the board, is that possible?
I enjoy all the input I can get. My goal is to have some fun. In addition to this, I think it would be great to have a board that costs less than the BB2+Bap28 and provides the user with that level of functionality with some added bonuses, like More code space, runs faster, USB/USART for SIN/SOUT, more IO lines…
I only have 8 analog pins as that is all the Analog pins that the H8/3687 chip has. The arc32 has 16, but it does so by using MUXS on the chip and adds the additional complexity of changing APIS… Yes I think I should have jumpers up for VS/VL connected up to 2 of the Analog ports, like the BB2.
As I mentioned, I am trying to provide the user with at least the functionality of BB2. But I am making some changes, like the ability for the user to use the buttons and LEDS independent of each other. One thing I have considered in some of these designs is some form of volume control for the speaker as my office is near the bedroom, but so far I usually solve that by putting a piece of electrical tape over the speaker
An XBee holder would be nice, but I think it would be hard to fit it on the 3x2.3" board.
Will be interesting to see if we come up with something that makes sense.
I did another layout using the right template (I think) for the Bap64. I also got in 3 pin headers for digital pins 0-31 and for the 8 Analog pins P40-P47. Added jumpers for VS/VL to P40, P41… Probably as far as I want to take it until we figure out what is best for USB and power…
I know that we all have our hands full with the Prop board and the Botboarduino board, and maybe Botboarduino Mega, assuming a reasonable shield???
But suppose I wanted to make a few boards with the Bap64 for myself and maybe a few friends if they wanted them and not make a production type board. Not saying I am going there yet… But if I were, to make things easier, I would consider not putting the USB to serial on the board, but probably instead use something like a Prop Plug (parallax.com/Store/Microcont … fault.aspx)
If I look at the schematic of the Prop plug correctly it looks like it would allow me to install a 4 pin header and then I could remove the usb connector, the FT232RL… Which would leave only one hard thing to solder which is the 64 pin chip… I believe the Prop plug is setup to control the reset line using the DTR signal, which I believe studio handles, so I think it might work.
As I see it the pros of this approach would be:
1)Lower cost per board
2)Easier to build
3)Less Comm port number expansion… I am up to Com24. Would be nice to simply plug the one in to the board I wish to work with and not have to keep updating the Com port in IDE, termainal,…
4)Easier to add extension wire/cables. Suppose I put a new board with USB inside my robot, how do I plug in the cable to program it? With USB it is hard to mount some extension cable, with Prop plug it is easy to mount an extension cable.
5) Power usage? Not sure here, but if the board is running without the dongle, will it consume less energy than the board with the built in USB chips if not plugged into USB?
But the cons are:
Higher cost for single board - That is it probably would cost a bit more to build 2 things than 1, so for user of only one thing, may not make sense
Confusion factor: Another place for the user to screw up…
Dongles can be lost, break… Like I don’t know where mine is right now…
This does not give the option to have the board run off of USB power.
Maybe? Would need to play around some and see if there is enough room for it. I guess the question then would be, what pins to hook up and where. The obvious candidates are for TXD2/RXD2. May also want the RTS line as well. Jumpers to enable? Or just the fact that it is plugged in. Would probably also need some voltage conversion.
Have not had much time to play here yet, been busy with other things. But I started to look at XBee as this may be a common theme as Mike mentioned maybe XBee on new SSC-32 if space permitting… As with all of these types of things there always appear to more options than I have answers for as I am very new to trying to design a board. There are simple questions like should the 20 pin header for the XBee be through hole or SM. Newer Sparkfun versions are using SM, the Parallax one I have is still through hole. Here I can simply choose (Sparkfun and Digikey have both parts).
Voltage Regulators: The XBees need 3.3V so need some form of voltage regulator. I am not 100% sure which one it is, but it looks like the same one on the Parallax kit one, which is a Fairchild FAN2500S33x which is rated for 100ma, which as their document ion states is good enough for standard XBees, but the XBee Pros can draw more than this. The Parallax SIP version uses an LM2937-3.3 which can deliver the power but is more expensive and takes more room… So the question is which way do you design? For me the lesser ones are just fine, but I have not been trying to do do Xbees a mile from each other…
Voltage conversion: The parallax uses true voltage conversion chip (74lVC244A), Sparkfun uses a diode to lower the voltage coming into DIN, and does no up conversion of DOUT. So far the sparkfun adapters appear to work on BAPs, but I have seen several issues with Atmegas (Axon, Arduino), where the high was not high enough… I would probably choose the parallax way, but again more $ and space…
LEDS: I would assume an RSSI, DIN, DOUT leds so you can see if you have a connection and if you are communicating back and forth.
Bring out Other XBee IO pins? We obviously need the standard pins, and I make use of RTS, but should we bring out the other IO pins. Probably at a minimum, should add .1" pins for each, but not necessarily populate these pins. That way users could solder in pins and connect them up. Should probably also provide a pin out for the 3.3v…
Again not sure if this makes any sense or if I will actually get a layout that works and order them… But it is fun to think about. But If I do, I wonder about maybe increasing the size of the board to 3x3 with Bap like holes, like we mentioned in the Arduino Mega thread.
I have played around some more to see about fitting an XBee and I am not sure it will fit with all of the current functionality that I have currently on the board.
Here is an image showing the previous layout of the board, minus the USB stuff, I shoved down some stuff and the like. On the outside of the board I have some of the XBEE parts. Still don’t have any LEDS and resistors for them or external connectors to allow to tap into other functiions.
As you can probably tell, there still is not room for XBee in there. Might be able to do things like, delete switches, move analog pins to where the switches were and fit an xbee in the current hole up toward the top… But not sure… Also not sure if I did get it all to work if it would make sense to make any… As there would be lots of SMD components to solder on…
If I get inspired, I might try, but I do think I would need to trade off some other functionality. For me the easiest thing to lose is the buttons. I do like having them from time to time, but majority of the time I don’t use them… The other possible option would be to change form factor, like was mentioned in the Arduino thread to 3x3 with hole patterns for that and current board size. Would work for many of the robots, but not all.
I deleted the 3 buttons, Have not done anything with those IO lines, but with that it appears like most things could fit, as you can see in this picture:
Note: I have not completed the routing of the board… Also If I go foreword I have questions to myself, on the 2 10 pin connectors for XBEE stuff, should I have those directly go to the XBEE (3.3v) or should I have the main ones go through the voltage converter chip such that they will have +5v compatible signals… Also wonder about converting more of the discrete components from the 0805 size to the 0603 size which would save some room…
That is about all I will do for now… Hoping that soon we will be able to concentrate again on Propeller, Botboarduino (JR and Mega???)
I know that this is probably a dead issue, but someone up on the BasicMIcro web site was talking about mounting on of the Bap64 chips onto a board using a hot plate… Which made me look up the state of the board I was playing around with.
So I cleaned up the layout a little. Replaced all 0603 caps with 0805… Also changed to the USB connector that we went with for BBJR. While I was doing this, I also added in pads for the potential solder in wires for an external USB connector. Why? Well first off Tuesday, I broke off the USB connector off of my 2nd Seeedunio Mega board. They are not through soldered… Not sure how easy it will be to solder on a new one. May need to get the jumper wire and solder it directly to FTDI chip…
2nd reason, if you wish to mount the board inside something like a remote control and you want to mount an external USB cable, you could simply solder the wires into the board… Maybe something to think about adding to next version of BBJR.
