From 361e11b3a7c0c5a581a3f30e2840fcb78875c7d8 Mon Sep 17 00:00:00 2001
From: Dirk Best <mail@dirk-best.de>
Date: Thu, 13 Feb 2025 13:12:52 +0100
Subject: [PATCH] mos8520: tod is not latched when CRB_ALARM is set

---
 src/devices/machine/mos6526.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/devices/machine/mos6526.cpp b/src/devices/machine/mos6526.cpp
index fae0b8618bc..f267a678e07 100644
--- a/src/devices/machine/mos6526.cpp
+++ b/src/devices/machine/mos6526.cpp
@@ -926,7 +926,9 @@ uint8_t mos8520_device::read(offs_t offset)
 	switch (offset & 0x0f)
 	{
 	case TOD_MIN:
-		if (!m_tod_latched)
+		// tod is not latched when CRB_ALARM is set
+		// test case: amigaocs_flop:batman1
+		if (!m_tod_latched && !CRB_ALARM)
 		{
 			m_tod_latched = true;
 			m_tod_latch = m_tod;