feat(fpga): make FT2232H default USB interface, rewrite FT601 write FSM, add clock-loss watchdog
- Set USB_MODE default to 1 (FT2232H) in radar_system_top.v; 200T build
overrides to USB_MODE=0 via build_200t.tcl generic property
- Rewrite FT601 write FSM: 4-state architecture with 3-word packed data,
pending-flag gating, and frame sync counter
- Add FT2232H read FSM rd_cmd_complete flag, stream field zeroing, and
range_data_ready 1-cycle pipeline delay in both USB modules
- Implement clock-loss watchdog: ft_heartbeat toggle + 16-bit timeout
counter drives ft_clk_lost, feeding ft_effective_reset_n via 2-stage
ASYNC_REG synchronizer chain
- Fix sample_counter reset literal width (11'd0 -> 12'd0)
- Add FT2232H I/O timing constraints to 50T XDC; fix dac_clk comments
- Document vestigial ft601_txe_n/rxf_n ports (needed for 200T XDC)
- Tie off AGC ports on TE0713 dev wrapper
- Rewrite tb_usb_data_interface.v for new 4-state FSM (89 checks)
- Add USB_MODE=1 regression runs; remove dead CHECK 5/6 loop
- Update diag_log.h USB interface comment
Jason
f393e96d69