Byte Hamr Labs

Logic analyzer proof of concept: live captures on HIRES with marker deltas that match the signal

/ Byte Hamr / updated 2026-09-11 / from project_byte_hamr logic-analyzer rev1 sdram hires 6502

What I tried

The whole pipeline: probes into the FPGA, samples written to SDRAM at 1 MHz, a trigger that arms, waits and snaps on the configured edge, decimated data read back over the bus, and 6502 code drawing 8 channels on HIRES. The 80-column text area at the bottom shows cursor position, A and B markers with their delta, trigger config and the zoom preset. Four zoom windows: 38 us, 88 us, 133 us and 266 us. The cursor moves pixel by pixel with a time readout in microseconds. Sample rate came in at 1 MHz, down from the 2 MHz I planned in January.

The analyzer program assembling in Merlin Pro on the IIe: 3106 bytes, no errors.
The analyzer program assembling in Merlin Pro on the IIe: 3106 bytes, no errors.
Empty state. Borders drawn, status line live, trigger set to CH3 rising, no capture yet.
Empty state. Borders drawn, status line live, trigger set to CH3 rising, no capture yet.
Zoom 1, a 38 us window, A and B markers on one pulse. Delta reads 4 us.
Zoom 1, a 38 us window, A and B markers on one pulse. Delta reads 4 us.
Zoom 2, an 88 us window, with A and B markers dropped and the delta in the status line.
Zoom 2, an 88 us window, with A and B markers dropped and the delta in the status line.
Zoom 3, a 133 us window.
Zoom 3, a 133 us window.
Zoom 4, a 266 us window. The 500 kHz channels at the top are too dense to resolve at this zoom.
Zoom 4, a 266 us window. The 500 kHz channels at the top are too dense to resolve at this zoom.

What I measured

What broke or surprised me

It is a proof of concept with rough edges. There is no paging through the capture buffer; the data is in SDRAM but the display cannot scroll to it. There is no continuous or roll mode. The button debounce capture I wanted as the demo is in the buffer but needs deeper zoom and paging to see. Precision is not lab grade. I am not chasing these now.

Next

Fuji Hamr: FujiNet-compatible storage on the same card, which means emulating a Liron card. Same PCB, same SDRAM, same bus interface, different gateware.