diff --git a/src/emu/diserial.c b/src/emu/diserial.c
index 1cd1ed93044..338fbde2544 100644
--- a/src/emu/diserial.c
+++ b/src/emu/diserial.c
@@ -16,6 +16,7 @@ device_serial_interface::device_serial_interface(const machine_config &mconfig,
 	m_df_stop_bit_count(STOP_BITS_0),
 	m_rcv_register_data(0x8000),
 	m_rcv_flags(0),
+	m_rcv_bit_count_received(0),
 	m_rcv_bit_count(0),
 	m_rcv_framing_error(false),
 	m_rcv_parity_error(false),