From f4a50aa85038e6ffbea62dc80a58f9bd642c5b0b Mon Sep 17 00:00:00 2001
From: AJR <ariedlmayer@gmail.com>
Date: Tue, 19 Nov 2024 19:16:08 -0500
Subject: cdp1852: Fixes and enhancements - Fix clock write handler - Add write
 handler for automatically clocking 8-bit data into input-mode latch - Add
 line read handler for SR output

---
 src/devices/machine/cdp1852.cpp | 36 ++++++++++++++++++++++++++++++++----
 src/devices/machine/cdp1852.h   |  2 ++
 2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/src/devices/machine/cdp1852.cpp b/src/devices/machine/cdp1852.cpp
index caa4f2517ad..8957590f4e4 100644
--- a/src/devices/machine/cdp1852.cpp
+++ b/src/devices/machine/cdp1852.cpp
@@ -103,7 +103,7 @@ void cdp1852_device::device_reset()
 
 void cdp1852_device::clock_w(int state)
 {
-	if (m_clock_active != bool(state))
+	if (m_clock_active == bool(state))
 		return;
 
 	m_clock_active = bool(state);
@@ -116,7 +116,7 @@ void cdp1852_device::clock_w(int state)
 			m_data = m_read_data(0);
 
 			// signal processor
-			set_sr_line(0);
+			set_sr_line(false);
 		}
 		else
 		{
@@ -159,7 +159,18 @@ void cdp1852_device::set_sr_line(bool state)
 
 TIMER_CALLBACK_MEMBER(cdp1852_device::update_do)
 {
-	m_write_data(param);
+	if (!m_read_mode())
+	{
+		// input data into register
+		m_data = param;
+
+		// signal processor
+		set_sr_line(false);
+	}
+	else
+	{
+		m_write_data(param);
+	}
 }
 
 
@@ -192,7 +203,7 @@ uint8_t cdp1852_device::read()
 
 
 //-------------------------------------------------
-//  write - data write
+//  write - data write (synchronous)
 //-------------------------------------------------
 
 void cdp1852_device::write(uint8_t data)
@@ -205,3 +216,20 @@ void cdp1852_device::write(uint8_t data)
 		m_new_data = true;
 	}
 }
+
+
+//-------------------------------------------------
+//  write_strobe - data write with asynchronous
+//  clock strobe
+//-------------------------------------------------
+
+void cdp1852_device::write_strobe(uint8_t data)
+{
+	if (!m_read_mode())
+	{
+		// output data
+		m_update_do_timer->adjust(attotime::zero, data);
+
+		m_clock_active = false;
+	}
+}
diff --git a/src/devices/machine/cdp1852.h b/src/devices/machine/cdp1852.h
index 7727715ee47..04ada134986 100644
--- a/src/devices/machine/cdp1852.h
+++ b/src/devices/machine/cdp1852.h
@@ -39,10 +39,12 @@ public:
 
 	uint8_t read();
 	void write(uint8_t data);
+	void write_strobe(uint8_t data);
 
 	void clock_w(int state);
 
 	uint8_t do_r() { return m_data; }
+	int sr_r() { return m_sr; }
 
 protected:
 	// device-level overrides
-- 
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