From 27812520eba28a4f6e887692be7566cfa848ec89 Mon Sep 17 00:00:00 2001
From: tmk <hasu@tmk-kbd.com>
Date: Fri, 8 May 2020 21:31:50 +0900
Subject: [PATCH] core: ibmpc: Add comments on stop bit of Z-150 AT

---
 tmk_core/protocol/ibmpc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tmk_core/protocol/ibmpc.c b/tmk_core/protocol/ibmpc.c
index 6fb949e7..65e8a267 100644
--- a/tmk_core/protocol/ibmpc.c
+++ b/tmk_core/protocol/ibmpc.c
@@ -293,6 +293,8 @@ ISR(IBMPC_INT_VECT)
         case 0b01010000:
         case 0b11010000:
             // AT-done
+            // DO NOT check stop bit. Zenith Z-150(AT) asserts stop bit as low for no reason.
+            // https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-AT-Keyboard-Protocol#zenith-z-150-beige
             // TODO: parity check?
             isr_state = isr_state>>6;
             ibmpc_protocol = IBMPC_PROTOCOL_AT;
-- 
2.47.1