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author angelosa <lordkale4@gmail.com>2025-12-06 12:20:10 +0100
committer angelosa <lordkale4@gmail.com>2025-12-06 12:21:16 +0100
commitac0078a60285c3f5e60c12a75c43eb63199a5c34 (patch)
treedb6c212640bed41962c7316d64d399ea8c309a61
parent9ca5e2e2a6249cc8cbc54eda40333e046acd29c6 (diff)
machine/mc68328.cpp: ignore lower 3 bits for IVR writes
-rw-r--r--src/devices/machine/mc68328.cpp5
1 files changed, 3 insertions, 2 deletions
diff --git a/src/devices/machine/mc68328.cpp b/src/devices/machine/mc68328.cpp
index 2451f7359bd..72e216d7ed4 100644
--- a/src/devices/machine/mc68328.cpp
+++ b/src/devices/machine/mc68328.cpp
@@ -1276,8 +1276,9 @@ u8 mc68328_base_device::irq_callback(offs_t offset)
void mc68328_base_device::ivr_w(u8 data) // 0x300
{
- LOGMASKED(LOG_INTS, "%s: ivr_w: IVR = %02x\n", machine().describe_context(), data);
- m_ivr = data;
+ // lower three bits are ignored on writes (pls1000 cares)
+ LOGMASKED(LOG_INTS, "%s: ivr_w: IVR = %02x (%02x)\n", machine().describe_context(), data & 0xf8, data);
+ m_ivr = data & 0xf8;
}
u8 mc68328_base_device::ivr_r() // 0x300