diff --git a/src/devices/cpu/nec/v5x.cpp b/src/devices/cpu/nec/v5x.cpp
index c071aa958b1..533a112a7a4 100644
--- a/src/devices/cpu/nec/v5x.cpp
+++ b/src/devices/cpu/nec/v5x.cpp
@@ -398,8 +398,8 @@ void v50_device::device_add_mconfig(machine_config &config)
 	m_tcu->out_handler<0>().set(m_icu, FUNC(pic8259_device::ir0_w));
 }
 
-v5x_base_device::v5x_base_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock)
-	: v33_base_device(mconfig, type, tag, owner, clock, address_map_constructor(FUNC(v5x_base_device::internal_port_map), this))
+v5x_base_device::v5x_base_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock, address_map_constructor port_map)
+	: v33_base_device(mconfig, type, tag, owner, clock, port_map)
 	, m_tcu(*this, "tcu")
 	, m_dmau(*this, "dmau")
 	, m_icu(*this, "icu")
@@ -408,17 +408,17 @@ v5x_base_device::v5x_base_device(const machine_config &mconfig, device_type type
 }
 
 v50_device::v50_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
-	: v5x_base_device(mconfig, V50, tag, owner, clock)
-{
-}
-
-v53_device::v53_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
-	: v5x_base_device(mconfig, V53, tag, owner, clock)
+	: v5x_base_device(mconfig, V50, tag, owner, clock, address_map_constructor(FUNC(v50_device::internal_port_map), this))
 {
 }
 
 v53_device::v53_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock)
-	: v5x_base_device(mconfig, type, tag, owner, clock)
+	: v5x_base_device(mconfig, type, tag, owner, clock, address_map_constructor(FUNC(v53_device::internal_port_map), this))
+{
+}
+
+v53_device::v53_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
+	: v53_device(mconfig, V53, tag, owner, clock)
 {
 }
 
diff --git a/src/devices/cpu/nec/v5x.h b/src/devices/cpu/nec/v5x.h
index 25fe7b123b9..6cff7c3bd91 100644
--- a/src/devices/cpu/nec/v5x.h
+++ b/src/devices/cpu/nec/v5x.h
@@ -44,7 +44,7 @@ public:
 	auto syndet_handler_cb() { return subdevice<v5x_scu_device>("scu")->syndet_handler(); }
 
 protected:
-	v5x_base_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock);
+	v5x_base_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock, address_map_constructor port_map);
 
 	// device_interface overrides
 	virtual void device_add_mconfig(machine_config &config) override;
@@ -55,7 +55,6 @@ protected:
 	// device_execute_interface overrides
 	virtual void execute_set_input(int inputnum, int state) override;
 
-	virtual void internal_port_map(address_map &map) = 0;
 	virtual void install_peripheral_io() = 0;
 
 	DECLARE_WRITE8_MEMBER(BSEL_w) {}
@@ -116,7 +115,7 @@ protected:
 	virtual void device_start() override;
 	virtual void device_reset() override;
 
-	virtual void internal_port_map(address_map &map) override;
+	void internal_port_map(address_map &map);
 	virtual void install_peripheral_io() override;
 
 	DECLARE_WRITE8_MEMBER(OPCN_w);
@@ -151,7 +150,7 @@ protected:
 	virtual void device_start() override;
 	virtual void device_reset() override;
 
-	virtual void internal_port_map(address_map &map) override;
+	void internal_port_map(address_map &map);
 	virtual void install_peripheral_io() override;
 
 	DECLARE_WRITE8_MEMBER(SCTL_w);