So, it looks like the digispark pro addresses several of my issues with the original digispark, namely it can now be used on a standard breadboard/perfboard, has more pins, has some sort of serial support.
Yep - your feedback was certainly some of the feedback I referenced when designing it!
I have some other questions though about the board:
Do the support libraries ditch the Tiny* libraries and use the standard include files and library names that are used in the Arduino? In particular, I have various microprocessors (Teensy 3.0, Uno R3, Pro Mini, Digispark, Gemma, Trinket, etc.) and I find I am less inclined to use the ATtiny85 processors due to having to change the code to use TinyWireM.h instead of Wire.h (and of course #ifdef out use of serial).
From the next release forward Digispark and Digispark Pro will have compatible Wire libraries based on TinyWire - no changes needed to use them with existing I2C libraries.
I haven't gotten into servos or motors as much, but I would have the same issue there (due to the ATtiny85 not having 16-bit timers).
Timer heavy libraries like some of the servo libraries will always need to be written to work explicitly with different MCUs due to the timer differences - but I suspect more will work out of the box with the attinys as they grow in popularity in the Arduino world. Motors/motor drivers have never needed any special consideration in my use - they tend to just use PWM inputs.
Is the board is more like a Leonardo than an Uno, in that serial.print only goes to the USB, and if you want it to go to the serial line, you would use serial1 (or serial0, etc.)? Or is it like the Uno in that serial.print will go to both the USB and RX/TX lines, and you shouldn't use those pins when debugging.
Serial is the USB serial device
Serial1 is the hardware UART
Can I setup the digispark pro so that I can re-program it from the computer without having to press a reset button or power cycle the board? I.e. does it honor the DTR emulation in USB?
No - this isn't possible with the way the bootloader works - for this to work the USB code would have to keep running, watching for that signal, and doing a reset when it sees it - which isn't practical on these small resource limited MCUs. Someone could add support for that - but it would have its own set of disadvantages. If one used an FTDI or secondary USB to Serial converter chip then they could do this with the attiny167 - but that would push the price too high in my opinion.
You mention solder jumpers underneath the digispark pro. Exactly what jumpers are available?
Disconnect LED, disconnect power LED, disconnect Zener for USB+, disconnect Zener and pull-up for USB-
Does your I2C pins have the 4.7K ohm resistors in place, or like the original digispark, will we have to provide these? What other pins have resistors on them (I assume pin 1 has the resistor for the LED, and the USB data pins do as well).
No I2C pullups - that would mess a lot of people up. I may put footprints on the bottom to solder them - but only if layout allows (right now it doesn't)
Pin1 has a 1K feeding the LED
Pin3 has 1.5k pull up
both can be detached by the solder jumper
Pin3 & 4 have low value resistors in series with the USB lines but not the headers, so they should have little effect on the pin usage
You use a micro-USB connector on the pro. While that is the standard connector these days, I've seen a lot of complaints in the various forums that the normal micro-USB connector isn't that good for repeated insertions and deletions. Are you going to strengthen the solder connections on the digispark pro so that it will have less chance to come apart?
It uses a micro usb (I don't care for the mini usb, it's big and the cables are less and less common) - I think the only reason the micros have a bad rep is 1) some of the people who had issues with them on projects like Mojo were very vocal about it and 2) some people use really cheap ones with a bad footprint that doesn't put enough solder under the case of the connector. Despite that I don't buy into the idea that they are so flawed (I've never broke a single one, even the cheap ones, except one that didn't have solder under the case) - the prototypes are using ones with thru hole reinforcement pins - and I plan to use those in the final version as well. These were used on the DigiX as well.
There is no 3.3v pin, so I assume mixed voltage projects will need an appropriate buck converter. Is this true?
Shields for 3.3v devices will integrate a LDO regulator - no need for a buck (unless it is a super low power use) - just a cheapo LDO will do without too much power loss. We have a 3.3v version of the Pro as well - but at 3.3v running it fast enough for USB isn't stable (a lesson the trinket has taught many). While I know some power users want 5v and 3.3v pins, in general it is one of the least requested things, and would represent significant extra cost.
I burned out one of my sparks hooking up a neopixel ring to VCC instead of VIN (with power from USB). While it was my fault, are the voltage regulators and fuses on the pro more able to protect us from dumb mistakes?
It is very likely it will have a fuse, it will have a more robust diode - were still playing with the sweet spot of pros and cons of these things, as well as what we can do with the limited space - we have a final version with and without a 500ma fuse on the 5v line
You don't mention what processor is actually used on the pro. Was I correct in my guess that it uses the ATtiny167?
Assuming it is the ATtiny167, the ATtiny167 can do touch sensing. Are you planning on releasing a touch interface so that we can do touch sensing in our projects?
Yep Attiny167
Thats the first time anyone has ever asked for touch shield - it'd be fun to make, I'll see if others are interested as well.
Do you have an idea what the general retail price will be after the kickstarter phase?
More than the Kickstarter price - that's all I know - these cost a lot more to make than the original Digispark, but I felt strongly about having them $10 or under. We'll have to see after we talk with our major distributors but I have a feeling it will be about $12 and the original Digispark may come down a bit in price when the Pros hit retail.