RH01T9k, the FPGA That Pretends to Be a Sensor

Field notes

RH01T9k uses a Tang Nano 9k FPGA board as a programmable stand-in for an SPI sensor or peripheral. A Python API sends configuration over UART, while the target firmware continues talking over the physical SPI bus as though the real device were present. The documented implementation supports all four SPI modes up to 20 MHz, a 256-byte register space, sequential and burst access, and MOSI/MISO capture. Fault injection and custom command mapping are listed as planned additions.