239 tnt's variant of SKY130 mini-MOSbius
239 : tnt's variant of SKY130 mini-MOSbius
- Author: Sylvain Munaut
- Description: Alternative layout for Andrew Kang's mini-MOSbius for SKY130 TinyTapeout
- GitHub repository
- Open in 3D viewer
- Open in Tiny Tapeout Explorer
- Clock: 0 Hz
How it works
The original MOSbius project by Peter Kinget et al. is a custom chip with basic MOS devices and building blocks interconnected by a reconfigurable array of analog switches to be able to build circuits and experiment with analog circuit design.
Matthew Venn commissioned an adaptation of the concept to fit on Tiny Tapeout Skywater shuttles and a proposal by Andrew Kang was accepted. See the attached document.
Andrew completed the schematic design along with simulation end of August 2025 but before he started the layout, I decided to use this as a base to build my own variant.
I left he design of the analog part is pretty much unchanged, only made minor adaptations. Some of those were guided by layout constraints, some other in an attempt to make more circuits possible. I did rewrite most of the digital control logic. And of course the layout is entirely mine.
How to test
A configuration bitstream needs to be loaded serially to control all the analog switches on-board. The software suite to generate this is yet to be written.
External hardware
Depends on what circuit you want to build and how you want to test it ...
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | data_in | data_out | |
| 1 | enable | ||
| 2 | |||
| 3 | |||
| 4 | |||
| 5 | |||
| 6 | |||
| 7 |
Analog pins
ua | PCB Pin | Internal index | Description |
|---|---|---|---|
| 0 | K | 5 | Reference Bias |
| 1 | C | 0 | Bus 1A |
| 2 | J | 4 | Bus 3A |
| 3 | D | 1 | Bus 5A |
| 4 | G | 3 | Bus 2B |
| 5 | F | 2 | Bus 4B |