xt_usb: Fix XT soft reset

[max/tmk_keyboard.git] / tmk_core / protocol / ibmpc.c

diff --git a/tmk_core/protocol/ibmpc.c b/tmk_core/protocol/ibmpc.c
index c2400dc5b68eaa0bade4bdda10a9e7db985e73c7..5f2ca79b2fba9f1bd8067b46ed1d2ca8ca6044a1 100644 (file)
--- a/tmk_core/protocol/ibmpc.c
+++ b/tmk_core/protocol/ibmpc.c
@@ -105,13 +105,13 @@ int16_t ibmpc_host_send(uint8_t data)
 
     /* terminate a transmission if we have */
     inhibit();
-    wait_us(100); // 100us [4]p.13, [5]p.50
+    wait_us(100);    // [5]p.54
 
     /* 'Request to Send' and Start bit */
     data_lo();
     wait_us(100);
-    clock_hi();
-    WAIT(clock_lo, 10000, 1);   // 10ms [5]p.50
+    clock_hi();     // [5]p.54 [clock low]>100us [5]p.50
+    WAIT(clock_lo, 10000, 1);   // [5]p.53, -10ms [5]p.50
 
     /* Data bit[2-9] */
     for (uint8_t i = 0; i < 8; i++) {
@@ -135,14 +135,15 @@ int16_t ibmpc_host_send(uint8_t data)
     /* Stop bit */
     wait_us(15);
     data_hi();
+    WAIT(clock_hi, 50, 6);
+    WAIT(clock_lo, 50, 7);
 
     /* Ack */
-    WAIT(data_lo, 50, 6);
-    WAIT(clock_lo, 50, 7);
+    WAIT(data_lo, 50, 8);
 
     /* wait for idle state */
-    WAIT(clock_hi, 50, 8);
-    WAIT(data_hi, 50, 9);
+    WAIT(clock_hi, 50, 9);
+    WAIT(data_hi, 50, 10);
 
     // clear buffer to get response correctly
     recv_data = 0xFFFF;
@@ -252,8 +253,8 @@ ISR(IBMPC_INT_VECT)
     if (isr_state == 0x8000) {
         timer_start = t;
     } else {
-        // should not take more than 1ms
-        if (timer_start != t && (uint8_t)(timer_start + 1) != t) {
+        // This gives 2.0ms at least before timeout
+        if ((uint8_t)(t - timer_start) >= 3) {
             ibmpc_isr_debug = isr_state;
             ibmpc_error = IBMPC_ERR_TIMEOUT;
             goto ERROR;
@@ -358,12 +359,17 @@ 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?
             ibmpc_isr_debug = isr_state;
+            // stop bit check
+            if (isr_state & 0x8000) {
+                ibmpc_protocol = IBMPC_PROTOCOL_AT;
+            } else {
+                // Zenith Z-150 AT(beige/white lable) asserts stop bit as low
+                // https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-AT-Keyboard-Protocol#zenith-z-150-beige
+                ibmpc_protocol = IBMPC_PROTOCOL_AT_Z150;
+            }
             isr_state = isr_state>>6;
-            ibmpc_protocol = IBMPC_PROTOCOL_AT;
             goto DONE;
             break;
         case 0b01100000: