From 13473bbd4c7d1f5600f0ef1284a13a9fd98eac55 Mon Sep 17 00:00:00 2001
From: arbee <rb6502@users.noreply.github.com>
Date: Sat, 22 Apr 2017 23:28:47 -0400
Subject: [PATCH] New fixes fizzled out, back to the uglier set. (nw)

---
 src/mame/machine/mac.cpp    | 15 +++++++++++----
 src/mame/machine/macadb.cpp | 36 +++++++++++++++++-------------------
 2 files changed, 28 insertions(+), 23 deletions(-)

diff --git a/src/mame/machine/mac.cpp b/src/mame/machine/mac.cpp
index 43cac6789cf..8e3bc092fa3 100644
--- a/src/mame/machine/mac.cpp
+++ b/src/mame/machine/mac.cpp
@@ -1238,10 +1238,17 @@ WRITE_LINE_MEMBER(mac_state::mac_adb_via_out_cb2)
 	}
 	else
 	{
-		if (state)
-			m_adb_command |= 1;
-		else
-			m_adb_command &= ~1;
+		if (m_adb_timer_ticks > 1)
+		{
+			if (state)
+			{
+				m_adb_command |= 1;
+			}
+			else
+			{
+				m_adb_command &= ~1;
+			}
+		}
 	}
 }
 
diff --git a/src/mame/machine/macadb.cpp b/src/mame/machine/macadb.cpp
index f0f86fdefc8..49bc23b8762 100644
--- a/src/mame/machine/macadb.cpp
+++ b/src/mame/machine/macadb.cpp
@@ -637,18 +637,26 @@ TIMER_CALLBACK_MEMBER(mac_state::mac_adb_tick)
 	}
 	else
 	{
+		// for input to Mac, the VIA reads on the *other* clock edge, so update this here
 		if (!m_adb_direction)
 		{
 			m_via1->write_cb2((m_adb_send & 0x80)>>7);
-			m_adb_send <<= 1;
+			if (m_adb_timer_ticks != 9)
+			{
+				m_adb_send <<= 1;
+			}
 		}
-		else
+	
+		// do one clock transition on CB1 to advance the VIA shifter
+		m_adb_extclock ^= 1;
+		m_via1->write_cb1(m_adb_extclock);
+
+		if ((m_adb_direction) && (m_adb_timer_ticks > 1))
 		{
 			m_adb_command <<= 1;
 		}
 
-		// do one clock transition on CB1 to advance the VIA shifter
-		m_via1->write_cb1(m_adb_extclock ^ 1);
+		m_adb_extclock ^= 1;
 		m_via1->write_cb1(m_adb_extclock);
 
 		m_adb_timer_ticks--;
@@ -659,9 +667,8 @@ TIMER_CALLBACK_MEMBER(mac_state::mac_adb_tick)
 			if ((m_adb_direction) && (ADB_IS_BITBANG_CLASS))
 			{
 				adb_talk();
-				if((m_adb_last_talk == 2) && m_adb_datasize)
-				{
-					m_adb_timer_ticks = 8;
+				if((m_adb_last_talk == 2) && m_adb_datasize) {
+					m_adb_timer_ticks = 9;
 					m_adb_timer->adjust(attotime(0, ATTOSECONDS_IN_USEC(100)));
 				}
 			}
@@ -682,7 +689,7 @@ void mac_state::mac_adb_newaction(int state)
 		#endif
 
 		m_adb_state = state;
-		m_adb_timer_ticks = 8;
+		m_adb_timer_ticks = 9;
 
 		switch (state)
 		{
@@ -691,8 +698,6 @@ void mac_state::mac_adb_newaction(int state)
 				m_adb_direction = 1;    // Mac is shifting us a command
 				m_adb_waiting_cmd = 1;  // we're going to get a command
 				m_adb_irq_pending = 0;
-				m_adb_extclock = 1; // VIA output shifts on falling clock
-				m_via1->write_cb1(m_adb_extclock);
 				m_adb_timer->adjust(attotime(0, ATTOSECONDS_IN_USEC(100)));
 				break;
 
@@ -709,9 +714,6 @@ void mac_state::mac_adb_newaction(int state)
 						m_adb_send = m_adb_buffer[0];
 						m_adb_datasize--;
 
-						m_adb_extclock = 0; // VIA input shifts on rising clock
-						m_via1->write_cb1(m_adb_extclock);
-
 						// move down the rest of the buffer, if any
 						for (i = 0; i < m_adb_datasize; i++)
 						{
@@ -1124,9 +1126,7 @@ void mac_state::adb_vblank()
 				m_adb_waiting_cmd = 1;
 				this->adb_talk();
 
-				m_adb_timer_ticks = 8;
-				m_adb_extclock = 0; // VIA input shifts on rising clock
-				m_via1->write_cb1(m_adb_extclock);
+				m_adb_timer_ticks = 9;
 				this->m_adb_timer->adjust(attotime(0, ATTOSECONDS_IN_USEC(100)));
 			}
 			#if 0
@@ -1163,9 +1163,7 @@ void mac_state::adb_vblank()
 				m_adb_waiting_cmd = 1;
 				this->adb_talk();
 
-				m_adb_timer_ticks = 8;
-				m_adb_extclock = 0; // VIA input shifts on rising clock
-				m_via1->write_cb1(m_adb_extclock);
+				m_adb_timer_ticks = 9;
 				this->m_adb_timer->adjust(attotime(0, ATTOSECONDS_IN_USEC(100)));
 			}
 			#if 0