Updated Bobuino design.

I’ve been urged to put out the original Bobuino again, so I’ve been working on it the last couple of weeks.
Started out just making the USB interface easier, changing from FTDI chip to FTDI module and then adding offboard header.
Kept the SD card, ditched the uSD socket.
Changed the 3.3V level translation to 74HC4050, and added 74HC125 for MISO buffering.
Added headers so the unused buffers in each could be used later, and added pullups to prevent oscillations from floating inputs.
Kept the RS232 buffer and jumpers to allow it to be connected to Serial1 or not.
Ditched the JTAG header.
Added Gnd pins next to digital pins to allow easy button connections.
Added Power & Gnd pins next to analog pins to allow easy potentiometer connections.
Added duplicate pads for all headers so the IO pins can be accessed still when shields are installed.
Added pads so screw terminals can be added if desired.
Added extra pads to bring in power from a wallwart if desired, and add a protection diode for the SMD regulator if needed.
Moved the battery to the top of the board so it sits flat.
Lastly, added a prototype area - allow mounting a 315/433 MHz Rx or Tx module and wiring it to IO pins, or nrfL2401+ module, or up to a 20 pin DIP.
I’m gonna make 10, 5 are spoken for already, if there’s other interest I’ll order parts for more kits.
No idea on cost, have to price it out all still. Figure I’ll do a template for the SMD parts, and send it out as partial kit and folks can solder all the thru hole parts in.

Any thoughts?

PM sent

Ditched the JTAG header.
Doesn’t the JTAG interface allow using hard break points when doing source level debugging?
Added duplicate pads for all headers so the IO pins can be accessed still when shields are installed.
How about “fixing” the second set of pads to use normal spacing
so users can make their own shields from standard strip/proto boards?
Any thoughts?

I might be off, but from what I remember from looking at some of the older photos,
it looked like the 6 pin ISP header was not in same position as an UNO.
For shields like the ethernet shield that need to plug into the ISP header,
it would be useful the ISP header was in the in same position.

Users wanting to connect to JTAG can make an adapter to connect to JTAG device. JTAG uses 10-pin header, but there are not 10 signals, only 4 or 5 and then power Gnd.

Headers - I'll check that - have to redo the schematic to split them off.

ISP header is at the standard location so the one shield that plugs onto it can use it.

Is it the D8-D13 header that is off? Or both on that side?

C rossroads,

The board sounds interesting! One suggestion, is make the pins available for Tone AC library to use. On the previous board a pin was used by the SD card. Here is a link to the library Google Code Archive - Long-term storage for Google Code Project Hosting.

Pins 9 & 10 - ATmega328, ATmega128, ATmega640, ATmega8, Uno, Leonardo, etc.
Pins 11 & 12 - ATmega2560/2561, ATmega1280/1281, Mega
Ping 12 & 13 - ATmega1284P, ATmega644
Pins 14 & 15 - Teensy 2.
Pins 25 & 26 - Teensy++ 2.0

12 & 13 - how defined? My Bobuino uses 12 & 13 for SPI - no reason you can't use them for other stuff when D10 is not asserted for SD access. All pins are on the headers.

Teckel and I were working on making ToneAC work and here is an old message I sent you that shows the pins required. They were not all available on the Bobuino.

My old message to you through PM.

am working with Teckel on ToneAC and I am looking for pin 30 on the board. I know that it used for CS with the SDcard but, I am can not find another pin that is connected.

Here is the chip pin names that I need:

D8 = OC1A\ PD5
D30 = OC1B\PD4

I found pin 8 but, not pin 30 except for at the buffer chip.

All 32 IO are all brought out to headers this time.
I think last time I was thinking some pins would have a dedicated use & not brought out, this time all are brought out.

Sounds real good!

Okay, got the D8-D13 “copy” header moved to be on 0.1" pitch. Also moved the D22-D31 headers to be on 0.1" pitch.
Should allow 0.1" perfboard to be used for a shield.

It is quite a bit different but have you seen the Itead "duinos"?

What I like about the layout on these boards is that you can use
Arduino shields, add a header to use strip/proto boards, and plug
in headers from sensors to use any of the analog or digital pins.
Kind of the best of all worlds.
It does most of what the sensor shields do.
(Note the 3 pin header ordering of gnd, +v, S which allows direct connection to most servos)
I also like the 3v/5v switch and the 4 pin header for i2c.

--- bill

Not sure I can get 5V on a header near the D0-D19 headers and still take signals out to the screw terminals. Will take a look.

Also consider the power pins order/layout on the header rows.
Most boards and sensor/servo shields out there use
ground, power, signal


power, ground, signal

Just something to think about.

--- bill

Right now only Analg header has power with it, +5/Gnd there should be easy to swap.
The rest have the header, and the header duplicated with Gnd next to it. See Reply #8.
I think there is room to move the gnd header out, just not sure if 5V can be routed in between as it has to cross all the signals going out to the screw terminal holes.

Is there a standard for I2C?

Is there a standard for I2C?

Not really. It is a mess.
I have seen several different 4 pin "i2c" headers/connectors.
I have devices & shields with these pinouts:

  • gnd, power, data, clock
  • gnd, power, clock, data
  • power, gnd, data, clock
  • ground, data, clock, power
  • ground, clock, data, power

What I've noticed is that

  • gnd, power, data, clock
    seems to be fairly popular.
    It is used on the Itead "duino" boards I showed above, UNO & Mega sensor shields,
    and most of the i2c devices I have like, ebay DS1307 & DS3231 RTC modules, hd44780 LCD backpacks, etc...

Pull up some ebay devices and have a look.
(search for "arduino i2c")
Most of what I see for UNO/Mega sensor shields, lcd backpacks and RTC modules is

  • gnd, power, data, clock

While that is my favorite pinout,
there are other devices out there that use other pinouts, so
depending on what devices people have,
they may have a different preference.

--- bill

Cool, thanks. Will see if I can fit two of those in.

Alright, think I’ve all the power & gnd headers layed out as discussed, see what you think.