IXXBB1 Fujitsu Microelectronics, Inc., IXXBB1 Datasheet - Page 37

• Manufacturer Part Number: IXXBB1
• Description: 32-bit Proprietary Microcontroller Cmos Fr60 Mb91301 Series
• Manufacturer: Fujitsu Microelectronics, Inc.

• Operating mode
• Bus mode
• Access mode
• Bus Modes
• Bus mode0 (single chip mode) (only MB91302A)
• Bus mode 1 (internal ROM external bus mode)
• Bus mode 2 (External-ROM, external-bus mode)
The bus mode controls the operations of internal ROM and the external access function. It is specified with
the mode setting pins (MD2, MD1, and MD0) and the ROMA bit in mode data.
The access mode controls the external data bus width. It is specified with the WTH1 and WTH0 bits in the
mode register and the DBW1 and DBW0 bits in area configuration registers 0 to 7 (ACR0 to ACR7).
The FR family has three bus modes: bus mode 0 (single-chip mode), bus mode 1 (internal-ROM, external-bus
mode), and bus mode 2 (external-ROM, external-bus mode).
The MB91V301A supports only bus mode 2 (external-ROM, external-bus mode).
See “1. Memory Space” in CPU for details.
The internal I/O, 4 Kbytes D-bus RAM, 32 Kbytes F-bus RAM (FRAM) and 96 Kbytes F-bus ROM are valid,
while access to any other areas is invalid under this mode. The function of external pin is peripheral or general-
purpose port. The pin can not be used as the bus pin.
The internal I/O, D-bus RAM, F-bus RAM (FRAM) and F-bus ROM are valid, and access to areas where
external access is enabled will access external space under this mode. A part of an external terminal functions
as a bus terminal.
This mode enables internal I/O and D-bus RAM, in which any access is access to external space. Some
external pins serve as bus pins.
Bus mode
External ROM external bus
Internal ROM external bus
Single chip
32-bit bus width
16-bit bus width
8-bit bus width
MB91301 Series
Access mode
37