Datasheet

Rev.6.00 Oct.28.2004 page 55 of 1016
REJ09B0138-0600H
Section 3 MCU Operating Modes
3.1 Overview
3.1.1 Operating Mode Selection (H8S/2357 F-ZTAT Only)
The H8S/2357 F-ZTAT has eight operating modes (modes 4 to 7, 10, 11, 14 and 15). These modes are determined by the
mode pin (MD
2
to MD
0
) and flash write enable pin (FWE) settings. The CPU operating mode and initial bus width can be
selected as shown in table 3-1.
Table 3-1 lists the MCU operating modes.
Table 3-1 MCU Operating Mode Selection (H8S/2357 F-ZTAT Only)
MCU CPU
External Data
Bus
Operating
Mode FWE MD
2
MD
1
MD
0
Operating
Mode Description
On-Chip
ROM
Initial
Width
Max.
Width
0 0000— — — — —
11
210
31
4 1 0 0 Advanced On-chip ROM disabled, Disabled 16 bits 16 bits
51
expanded mode
8 bits 16 bits
6 1 0 On-chip ROM enabled,
expanded mode
Enabled 8 bits 16 bits
7 1 Single-chip mode — —
8 1000— — — — —
91
10 1 0 Advanced Boot mode Enabled 8 bits 16 bits
11 1 — —
12 100— — — — —
13 1
14 1 0 Advanced User program mode Enabled 8 bits 16 bits
15 1 — —
The CPU's architecture allows for 4 Gbytes of address space, but the H8S/2357 Group actually accesses a maximum of 16
Mbytes.
Modes 4 to 6 are externally expanded modes that allow access to external memory and peripheral devices.
The external expansion modes allow switching between 8-bit and 16-bit bus modes. After program execution starts, an 8-
bit or 16-bit address space can be set for each area, depending on the bus controller setting. If 16-bit access is selected for
any one area, 16-bit bus mode is set; if 8-bit access is selected for all areas, 8-bit bus mode is set.
Note that the functions of each pin depend on the operating mode.
Modes 10, 11, 14, and 15 are boot modes and user program modes in which the flash memory can be programmed and
erased. For details, see section 19, ROM.