Older designs
Two boards
For this project, I had developped a couple of boards, the un0rick and the lit3rick boards, based on the hx4k and up5k lattice fpga, respectively. Both are open hardware certified (check for un0rick and lit3rick ).
un0rick
lit3rick
Comparing the two designs
They have their own specificities:
| un0rick | lit3rick | |
|---|---|---|
| FPGA | HX4K, HX8K | UP5K |
| Onboard high voltage | 0, 24, 48, 72V | 5V |
| RAM | External 8Mb | Internal 1Mb |
| ADC | 64Msp, 10bits, interleaved at 128Msps | 64Msps 12 bits |
| Amplification / VGA | AD8331 | AD8331 |
| Pulser | Unipolar, 0 to 100V | Bipolar, -100V to 100V |
| Size | Larger | Raspberry pHAT size |
| USB capable | Yes (FTDI) | No |
ice40 - a specificity
These two boards build in particular on the famouse ice40 FPGA family which is low-cost, … and open-sourced.
It can use the “Project IceStorm”, which aims at reverse engineering and documenting the bitstream format of Lattice iCE40 FPGAs and providing simple tools for analyzing and creating bitstream files.
There’s a bit of action around these FPGAs these days, be it for tools, extensions, DIP designs,… and I thought using those for a ultrasound imaging device would permit to mix both FPGA and OpenSource.