The last stable board revision was rev.4. After doing test with beta revision 5 & 6, a new board revision is now available
While the form factor remains the same, there are a few enhancements in this new release :
- A power regulator to replace the light one on the blackpill
- Diode and power fuse to better protect the SmartDisk
- Resistor for future Mac floppy drive use.
- Pull-up resistor to replace stm32 internal ones
If you have a rev.4, there is no need to upgrade and the firmware new version will continue to work on the previous release.
On the revision 8, one need to be careful with the power source and avoid to use 5V and 3V power supply at the same time (or SDIO with 5V) otherwise it will blow up the SmartDisk. On the left side of the board, above the buzzer, there are to power supply rails with pads and jumpers
- 5V from the Apple II (after fuse and diode) : the blackpill is doing the power regulation
- 3V provided by the on board power regulator LM1117-3.3
Do not use both at the same time or it will fry the SmartDisk II
If you plan to use different OLED screen with higher power consumption, using the board power regulator instead of the one on the blackpill is really important.
If you use an external power source with the 3V pin on the STLink rail, the diode is an absolute need to avoid current back to the Apple II
The new resettable fuse is not mandatory and a bypass pad can be solder.
Additional pull-up resistors are also not mandatory and bypass pads can be soldered.
Power regulator and additional components use 805 type SMD footprint, however it is quite easy to solder, the best is to use thin thin solder approx 0.3 (with pb otherwise it does not give good result).
This new revision comes also with a clearer front and back silk to easy placing components.
