Datasheet

Rev.6.00 Oct.28.2004 page 564 of 1016
REJ09B0138-0600H
19.2 Register Descriptions
19.2.1 Mode Control Register (MDCR)
Bit:76543210
— — — — — MDS2 MDS1 MDS0
Initial value : 1 0 0 0 0 —* —* —*
R/W:————— R R R
Note: * Determined by pins MD
2
to MD
0
.
MDCR is an 8-bit read-only register that indicates the current operating mode of the H8S/2357 Group.
Bit 7—Reserved: This bit cannot be modified and is always read as 1.
Bits 6 to 3—Reserved: These bits cannot be modified and are always read as 0.
Bits 2 to 0—Mode Select 2 to 0 (MDS2 to MDS0): These bits indicate the input levels at pins MD
2
to MD
0
(the current
operating mode). Bits MDS
2
to MDS
0
correspond to pins MD
2
to MD
0
. MDS2 to MDS0 are read-only bits, and cannot be
written to. The mode pin (MD
2
to MD
0
) input levels are latched into these bits when MDCR is read. These latches are
canceled by a power-on reset, but are retained after a manual reset*.
Note: * Manual reset is only supported in the H8S/2357 ZTAT.
19.2.2 Bus Control Register L (BCRL)
Bit:76543210
BRLE BREQOE EAE LCASS DDS — WDBE WAITE
Initial value : 0 0 1 1 1 1 0 0
R/W : R/W R/W R/W R/W R/W R/W R/W R/W
Enabling or disabling of part of the H8S/2357’s on-chip ROM area can be selected by means of the EAE bit in BCRL.
For details of the other bits in BCRL, see section 6.2.5, Bus Control Register L (BCRL).
Bit 5—External Address Enable (EAE): Selects whether addresses H'010000 to H'01FFFF*
2
are to be internal addresses
or external addresses.
Bit 5
EAE Description
0 Addresses H'010000 to H'01FFFF*
2
are in on-chip ROM
1 Addresses H'010000 to H'01FFFF*
2
are external addresses (external expansion
mode)
or a reserved area*
1
(single-chip mode). (Initial value)
Notes: 1. Reserved areas should not be accessed.
2. Addresses H'010000 to H'01FFFF are in the H8S/2357. Addresses H'010000 to H'03FFFF are in the H8S/2398.