diff --git a/src/devices/bus/ata/px320a.cpp b/src/devices/bus/ata/px320a.cpp
index befaad3befd..fabad11e967 100644
--- a/src/devices/bus/ata/px320a.cpp
+++ b/src/devices/bus/ata/px320a.cpp
@@ -75,7 +75,7 @@ void px320a_device::frcpu_map(address_map &map)
 
 void px320a_device::device_add_mconfig(machine_config &config)
 {
-	MB91101A(config, m_frcpu, 8000000); // FR type guessed; clock unknown
+	MB91F155A(config, m_frcpu, 16'000'000); // FR type guessed; clock unknown
 	m_frcpu->set_addrmap(AS_PROGRAM, &px320a_device::frcpu_map);
 }
 
diff --git a/src/devices/cpu/fr/fr.cpp b/src/devices/cpu/fr/fr.cpp
index 07ecaad136f..187b2782a4f 100644
--- a/src/devices/cpu/fr/fr.cpp
+++ b/src/devices/cpu/fr/fr.cpp
@@ -12,8 +12,8 @@
 #include "fr.h"
 #include "frdasm.h"
 
-// device type definitions
-DEFINE_DEVICE_TYPE(MB91101A, mb91101a_device, "mb91101a", "Fujitsu MB91101A")
+// device type definition
+DEFINE_DEVICE_TYPE(MB91F155A, mb91f155a_device, "mb91f155a", "Fujitsu MB91F155A")
 
 fr_cpu_device::fr_cpu_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock, int addrbits, address_map_constructor map)
 	: cpu_device(mconfig, type, tag, owner, clock)
@@ -30,11 +30,17 @@ fr_cpu_device::fr_cpu_device(const machine_config &mconfig, device_type type, co
 {
 }
 
-mb91101a_device::mb91101a_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
-	: fr_cpu_device(mconfig, MB91101A, tag, owner, clock, 32, address_map_constructor())
+mb91f155a_device::mb91f155a_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
+	: fr_cpu_device(mconfig, MB91F155A, tag, owner, clock, 24, address_map_constructor(FUNC(mb91f155a_device::internal_map), this))
 {
 }
 
+void mb91f155a_device::internal_map(address_map &map)
+{
+	// TODO: I/O registers
+	map(0x001000, 0x008fff).ram();
+}
+
 std::unique_ptr<util::disasm_interface> fr_cpu_device::create_disassembler()
 {
 	return std::make_unique<fr_disassembler>();
diff --git a/src/devices/cpu/fr/fr.h b/src/devices/cpu/fr/fr.h
index c5b4899cace..3e931cbff87 100644
--- a/src/devices/cpu/fr/fr.h
+++ b/src/devices/cpu/fr/fr.h
@@ -2,11 +2,10 @@
 // copyright-holders:AJR
 
 #ifndef MAME_CPU_FR_FR_H
-#define MAME_CPU_FR_FR_H 1
+#define MAME_CPU_FR_FR_H
 
 #pragma once
 
-
 class fr_cpu_device : public cpu_device
 {
 public:
@@ -57,13 +56,17 @@ private:
 	s32 m_icount;
 };
 
-class mb91101a_device : public fr_cpu_device
+class mb91f155a_device : public fr_cpu_device
 {
 public:
 	// device type constructor
-	mb91101a_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock);
+	mb91f155a_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock);
+
+private:
+	void internal_map(address_map &map);
 };
 
-DECLARE_DEVICE_TYPE(MB91101A, mb91101a_device)
+// device type declaration
+DECLARE_DEVICE_TYPE(MB91F155A, mb91f155a_device)
 
 #endif // MAME_CPU_FR_FR_H