From fdc38ef3f92af7adeeb4de49550d8838c8a39b5c Mon Sep 17 00:00:00 2001
From: Jun Wako <wakojun@gmail.com>
Date: Thu, 24 Sep 2015 12:29:11 +0900
Subject: Squashed 'tmk_core/' changes from dc0e46e..57d27a8

57d27a8 Merge branch 'core_update_150924' into core
024abe3 core: Fix NKRO ifdef
7aa2d30 core: Fix for disabling NKRO in Boot protocol
95651fd core: Fix message print of debug command
c20cd29 lufa: Fix endpoint bank mode for ATMega32u2
82ac21f next_usb: Fix next_kbd_set_leds()
537d9c7 Change to KC_BOOTLOADER(KC_BTLD)
f2b3772 Add an assignable RESET key
fc99257 Fix parenthesis
e852582 Fix weak modifier clear in action macro
c2a6c5c core: Fix lufa suspend callback(#234)
fa548c5 usb_usb: Ignore error usage(0x01-03) report
513d95c usb_usb: Support locking key indicator LED
cd78802 core: Add keymap section ldscript for ATMega32U2
70c9abd Add description for non-US keys on keycode.h
538c192 lufa: Fix console flush #223
87628c9 Revert "Make action_for_key a weak symbol"
3c0a1ba Make action_for_key a weak symbol
6bb0d7d ibm4704_usb: Fix protocol handling
b6ef5cf Add keyboard_setup() and matrix_setup()
f4bb8b2 ibm4704_usb: Fix interrupt of clock(rising edge)
0c1fcc1 usb_usb: Change debug LED pin config
595710d Reduce code size of magic commands
6bed174 Add description of AVR bootloader and boot section
54c6a01 Merge commit 'f6d56675f9f981c5464f0ca7a1fbb0162154e8c5'
d18d42e Merge branch 'core-update2' into core
febec88 Add compile options '-fdata-sections'

git-subtree-dir: tmk_core
git-subtree-split: 57d27a8e39173a589b4abae74851f95c39940174
---
 protocol/ibm4704.c | 45 ++++++++++++++++++++++-----------------------
 1 file changed, 22 insertions(+), 23 deletions(-)

(limited to 'protocol/ibm4704.c')

diff --git a/protocol/ibm4704.c b/protocol/ibm4704.c
index a10a5e74d..6a03cd441 100644
--- a/protocol/ibm4704.c
+++ b/protocol/ibm4704.c
@@ -21,9 +21,10 @@ uint8_t ibm4704_error = 0;
 
 void ibm4704_init(void)
 {
+    inhibit();  // keep keyboard from sending
     IBM4704_INT_INIT();
     IBM4704_INT_ON();
-    idle();
+    idle();     // allow keyboard sending
 }
 
 /*
@@ -104,51 +105,44 @@ uint8_t ibm4704_recv_response(void)
     return rbuf_dequeue();
 }
 
+uint8_t ibm4704_recv(void)
+{
+    if (rbuf_has_data()) {
+        return rbuf_dequeue();
+    } else {
+        return -1;
+    }
+}
+
 /*
 Keyboard to Host
 ----------------
 Data bits are LSB first and Parity is odd. Clock has around 60us high and 30us low part.
 
-        ____      __   __   __   __   __   __   __   __   __   ________
-Clock       \____/  \_/  \_/  \_/  \_/  \_/  \_/  \_/  \_/  \_/
+        ____       __   __   __   __   __   __   __   __   __   _______
+Clock       \_____/  \_/  \_/  \_/  \_/  \_/  \_/  \_/  \_/  \_/
              ____ ____ ____ ____ ____ ____ ____ ____ ____ ____    
 Data    ____/    X____X____X____X____X____X____X____X____X____X________
             Start   0    1    2    3    4    5    6    7    P  Stop
 
 Start bit:  can be long as 300-350us.
 Inhibit:    Pull Data line down to inhibit keyboard to send.
-Timing:     Host reads bit while Clock is hi.
+Timing:     Host reads bit while Clock is hi.(rising edge)
 Stop bit:   Keyboard pulls down Data line to lo after 9th clock.
 */
-uint8_t ibm4704_recv(void)
-{
-    if (rbuf_has_data()) {
-        return rbuf_dequeue();
-    } else {
-        return -1;
-    }
-}
-
 ISR(IBM4704_INT_VECT)
 {
     static enum {
-        INIT, START, BIT0, BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7, PARITY,
-    } state = INIT;
+        BIT0, BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7, PARITY, STOP
+    } state = BIT0;
     // LSB first
     static uint8_t data = 0;
     // Odd parity
     static uint8_t parity = false;
 
     ibm4704_error = 0;
-    // return unless falling edge
-    if (clock_in()) { goto RETURN; }    // why this occurs?
 
-    state++;
     switch (state) {
-        case START:
-            // Data:Low
-            WAIT(data_hi, 10, state);
-            break;
         case BIT0:
         case BIT1:
         case BIT2:
@@ -169,6 +163,10 @@ ISR(IBM4704_INT_VECT)
             }
             if (!parity)
                 goto ERROR;
+            break;
+        case STOP:
+            // Data:Low
+            WAIT(data_lo, 100, state);
             rbuf_enqueue(data);
             ibm4704_error = IBM4704_ERR_NONE;
             goto DONE;
@@ -176,13 +174,14 @@ ISR(IBM4704_INT_VECT)
         default:
             goto ERROR;
     }
+    state++;
     goto RETURN;
 ERROR:
     ibm4704_error = state;
     while (ibm4704_send(0xFE)) _delay_ms(1); // resend
     xprintf("R:%02X%02X\n", state, data);
 DONE:
-    state = INIT;
+    state = BIT0;
     data = 0;
     parity = false;
 RETURN:
-- 
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