Closing the day with the last roadmap rung. A thin wrapper that adapts P02 (counter/PWM/LFSR) into the Tiny Tapeout user-project pin frame.
What happened
Status: rtl-pass. This is not the actual TT submission — that has its own CI flow against fixed tile sizes — but a sanity-check build that confirms the pin shape synthesizes cleanly under our existing LibreLane harness.
The TT pin frame is a fixed module signature: tt_um_* name, 8 ui_in,
8 uo_out, 8 uio_in / 8 uio_out / 8 uio_oe (bidirectional pads that the
user controls on a per-pin basis), plus clk, rst_n, and ena (a
synchronous enable that the TT carrier asserts when this user project
gets selected from the multiplexer). Everything maps to one fixed
signature tt_um_librelane_p02.
Pin map for the wrapper:
ui_in[1:0] = mode (00 counter, 01 LFSR, 10 PWM, 11 zero)
uio_in[7:0] = threshold (PWM threshold)
uo_out[7:0] = mode-selected output
ena = synchronous enable on top of rst_n (mute outputs when low)
uio_oe = 0 (uio is input-only here)Tests verify the wrapper preserves P02’s behaviour: ena=0 mutes
outputs, the counter advances, PWM duty matches threshold. Running
P02’s own logic underneath means we trust the harden trail: the
inner module is the same one that landed at +1.24 ns slow-corner
slack in P02 back in the morning.
Roadmap status: 01-07 hardened, 08-10 rtl-pass. The ladder reaches the tenth rung. Tomorrow is for taking another swing at landing P08’s macro flow on a clean signoff.
Receipts
ac3c158— TT wrapper RTL + tests + librelane config- project page. (Same commit covers P08’s narrative rewrite — see the P08 entry.)
Project page: /projects/10_tiny_tapeout/.