What is the advantage of ATtiny85 chip versus the Digispark pcb?
Unit costs on eBay and Aliexpress are lower for the Digispark and you get a USB plug to boot. Only disadvantage (?) as could be seen is that programming the Digispark over USB not always is a ride in the park.
So, what to choose and for what reason, because I am clueless.
Erik
Digispark with micronucleus bootloader: 2k used (of 8k flash total). Seems a lot..
Yeah, it's got all that usb crap on it, and many come with rstdisbl set so it's no easy task to make them behave like a normal tiny85 that you can program via isp
That was a fairly emotional response:
Is there a more rational or pro versus contra approach to my question possible?
Thank you,
Erik
The point was that 25% of the memory is used by the bootloader. If you only have a 6K sketch, perhaps that's acceptable.
If reset disable is set so the Reset pin can be used as an additional IO pin, then High Voltage programming (12V) must be done to clear that fuse so that an External reset can be done - either via a Serial programmer (FTDI Basic for example, where DTR is used to create a reset and start the bootloader code), or ICSP, where a Programmer can hold Reset low while it accesses memory directly using the SCK/MOSI/MISO pins.
High voltage programmer:
brice3010:
What is the advantage of ATtiny85 chip versus the Digispark pcb?<...>
Ultimately, only the bootloader over USB and USB HID.
I have a Trinket clone (Trinket and DigiSpark are the same except for the firmware) and a Trinket Pro clone projects if you want a bit of deeper understanding.
Ray
mrburnette, does the "trinket" also have usb connection issues (I have major problems from time to time on one of my pc's (Win7 64bit) where I have "unknown device" days on end) as the Digispark has?
Personally I tend to favour the virgin ATtiny85 over the USB versions because of the 25% loss of memory. Otherwise the Digispark has pin5 free (at the cost of ISP uploading, but then that is why there is a USB connector. A bit of a quandary...
Cost factor: a Digispark clone can be had for less the €1; the ATtiny85 however cost about €1.20 starting with 5 pcs (DIP)!
Why would a straight virgin IC cost more then a pcb loaded with the same IC, a voltage regulator, pinheaders and other components??
brice3010:
mrburnette, does the "trinket" also have usb connection issues (I have major problems from time to time on one of my pc's (Win7 64bit) where I have "unknown device" days on end) as the Digispark has?
<...>
Why would a straight virgin IC cost more then a pcb loaded with the same IC, a voltage regulator, pinheaders and other components??
We really do not know the supply chain for the Chinese clone boards... But my guess is that DIP tiny85 are not in great demand therefore one pays more.
The USB connection issue, IMO, is basically a V-USB issue: the timing on the V-USB code is very close to USB 1.1 specs but not exact. It appears close 'nuff to work OK on XP vintage hardware. With USB 3.0 ports, I have often used a separate USB 1.1 hub to get stability... And even that is not perfect.
I have always considered V-USB a rainy day curiosity.
https://create.arduino.cc/projecthub/rayburne/arduino-to-excel-using-v-usb-cbf701
http://forum.arduino.cc/index.php?topic=135623.0
http://forum.arduino.cc/index.php?topic=195003.0
Ray
You know, you can have the best of both worlds, and complete flexibility. If you have a Digispark board, you can remove or tombstone the USB data line resistors or cut the traces to them if you don't plan to use V-USB. Then the board becomes an ATtiny85 breakout board with a USB power port and a 5V regulator that is usable through the VIN pin. With an Arduino such as Uno, a 12V battery, and a resistor, you have a high voltage programmer and you can restore the fuses. Then you can program and use it via ISP just like a stand-alone ATtiny85. You can program the reset disable fuse after sketch upload via ISP if your sketch uses pin PB5. Just do HV programming any time you need to unprogram the reset disable fuse to enable ISP programming again.
Your 'unknown device' problems are likely user error. If you don't know what you're doing, then it's essentially slander to blame the product unfairly.
I have both, but have taken to only using the bare ATTiny85 chips. My biggest reason is the flexibility in power sourcing. It doesn't demand 5V to only go through a regulator anyway. The ATTiny85 runs on something as simple as a CR2032 button battery, or a single 18650 cell, or 4 AA NiMHs.
Uploading on Digispark via USB is only a smidge easier to plug in than a bare chip. But I have an Uno and a mini breadboard that is dedicated just for the task of uploading to the bare ATTiny85. The difference is literally sticking the chip into a breadboard versus sticking a microusb cable into the Digi. Trivial.
INTP:
Your 'unknown device' problems are likely user error. If you don't know what you're doing, then it's essentially slander to blame the product unfairly.
I consider the first to be slander 
Power sourcing: same can be said for a Digispark?
mrburnette:
We really do not know the supply chain for the Chinese clone boards... But my guess is that DIP tiny85 are not in great demand therefore one pays more.The USB connection issue, IMO, is basically a V-USB issue: the timing on the V-USB code is very close to USB 1.1 specs but not exact. It appears close 'nuff to work OK on XP vintage hardware. With USB 3.0 ports, I have often used a separate USB 1.1 hub to get stability... And even that is not perfect.
I have always considered V-USB a rainy day curiosity.
String numeric output with V-USB HID - Exhibition / Gallery - Arduino Forum
V-USB enabled prototyping (Picture Review) - Device Hacking - Arduino Forum
Ray
Interesting view, good to know as i was not aware of this (V-USB issue).
dmjlambert:
You know, you can have the best of both worlds, and complete flexibility. If you have a Digispark board, you can remove or tombstone the USB data line resistors or cut the traces to them if you don't plan to use V-USB. Then the board becomes an ATtiny85 breakout board with a USB power port and a 5V regulator that is usable through the VIN pin. With an Arduino such as Uno, a 12V battery, and a resistor, you have a high voltage programmer and you can restore the fuses. Then you can program and use it via ISP just like a stand-alone ATtiny85. You can program the reset disable fuse after sketch upload via ISP if your sketch uses pin PB5. Just do HV programming any time you need to unprogram the reset disable fuse to enable ISP programming again.
Fully agree! The nice thing about these clones is that they (as far as I have experienced) have the pin1 fuse (reset) enabled.
brice3010:
Interesting view, good to know as i was not aware of this (V-USB issue).
V-USB was developed by Objective Development. Frank Zhao embellished the technology in his USnooBie product while he was still in college. Also, Frank made headlines with his USB Business Card. Frank went on to work as a software engineer for Adafruit where he developed the firmware for the Trinket and Trinket Pro and some utilities to bridge gaps. Around the time of the Trinket Pro, Frank moved on to another position.
DigiSpark did a lots of internal firmware development, but essentially had major problems finishing the code. Bluebie (Jenna Fox) stepped in and wrote micronucleus which is a viral bootloader. Both Adafruit's Trinket and the DigiSpark are V-USB based.
This Hackaday article discusses some of V-USB's shortcomings.
Ray
mrburnette:
V-USB was developed by Objective Development. Frank Zhao embellished the technology in his USnooBie product while he was still in college. Also, Frank made headlines with his USB Business Card. Frank went on to work as a software engineer for Adafruit where he developed the firmware for the Trinket and Trinket Pro and some utilities to bridge gaps. Around the time of the Trinket Pro, Frank moved on to another position.DigiSpark did a lots of internal firmware development, but essentially had major problems finishing the code. Bluebie (Jenna Fox) stepped in and wrote micronucleus which is a viral bootloader. Both Adafruit's Trinket and the DigiSpark are V-USB based.
This Hackaday article discusses some of V-USB's shortcomings.
Ray
Véry interesting!
Thks for this info, it helps in setting the Digispark in the right context!
Erik
brice3010:
Véry interesting!Thks for this info, it helps in setting the Digispark in the right context!
Erik
One interesting point is that DigiSpark's and Adafruit's libraries and example code (excepting the 3rd PWM of the DigiSpark) is essentially interchangeable. This broadens ones options.
UNO Shield with ZIF mod for attiny85
If you build your own V-USB device, the critical component is the 3.6V zener. My article gives a source. IN5227B-TAP. The timing issue created by a too-large junction capacitance is ugly.
Ray
I use the input on PORB.3 or on pin D3 digispark board. The input signal does not work on this Pin, when it is moved to another pin the input signal is ok and can work well. The check shows there is a voltage on pin D.3, how how to remove the voltage on the D3 pin digispark or PORTB.3, All your help and advice, I am very grateful.
