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feat(kernel): add debounced (glitch-filtered) sense-line reads #5

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chris wants to merge 14 commits from debounced-reads into master
pull from: debounced-reads
merge into: chris:master
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1 changed files with 10 additions and 1 deletions
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kernel/iec_listener.c
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@ -242,7 +242,16 @@ static enum iec_rx receive_byte(u8 *out, bool *eoi, bool data_phase)
value |= (1u << i);
}
/* 4. BYTE ACKNOWLEDGE: pull DATA low (Tf), hold for the next RFD */
/* 4. BYTE ACKNOWLEDGE: wait for the talker to pull CLK low at end of
* byte (mirrors the reference listener), THEN pull DATA low (Tf).
* Without this wait we would assert the ack while CLK is still high
* from bit 7, racing the talker's end-of-byte edge and desyncing the
* handshake. The next receive_byte() releases DATA after CLK goes high
* again (RFD), completing the per-byte handshake. */
rc = wait_clk(true /* asserted: talker finished the byte */,
IEC_CLK_TIMEOUT_US, data_phase);
if (rc != IEC_RX_OK)
goto out;
iec_data_assert();
*out = value;
rc = IEC_RX_OK;