SH7751 Datasheet, PDF (457/1224 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

13. Bus State Controller (BSC)
13.2.3 Bus Control Register 3 (BCR3) (SH7751R Only)
Bus control register 3 (BCR3) is a 16-bit readable/writable register that specifies the selection of
either the MPX interface or the SRAM interface and specifies the burst length when the
synchronous DRAM interface is used.
BCR3 is initialized to H'0001 by a power-on reset, but is not initialized by a manual reset or in
standby mode. No external memory space other than area 0 should be accessed before register
initialization has been completed.
Bit: 15
14
13
12
11
10
9
8
Bit name: MEMMODE A1MPX A4MPX —
—
—
—
—
Initial value: 0
0
0
0
0
0
0
0
R/W: R/W R/W R/W
R
R
R
R
R
Bit: 7
6
5
4
3
2
1
0
Bit name: —
—
—
—
—
—
—
SDBL
Initial value: 0
0
0
0
0
0
0
1
R/W: R
R
R
R
R
R
R
R/W
Bit 15⎯A1MPX/A4MPX Enable (MEMMODE): Determines whether or not the selection of
either the MPX interface or the SRAM interface is by A1MPX and A4MPX rather than by
MEMMPX.
Bit 15: MEMMODE
0
1
Description
MPX or SRAM interface is selected by MEMMPX
(Initial value)
MPX or SRAM interface is selected by A1MPX and A4MPX
Rev.4.00 Oct. 10, 2008 Page 359 of 1122
REJ09B0370-0400