diff --git a/src/mame/drivers/ympsr340.cpp b/src/mame/drivers/ympsr340.cpp
index 9cea741e737..a403d4ca51d 100644
--- a/src/mame/drivers/ympsr340.cpp
+++ b/src/mame/drivers/ympsr340.cpp
@@ -69,7 +69,7 @@ u8 psr340_state::matrix_r()
 
 	for (int i = 0; i < 8; i++)
 	{
-		if (!BIT(m_matrixsel, i))
+		if (BIT(m_matrixsel, i))
 		{
 			data |= m_key[i]->read();
 		}