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SH7751 Group, SH7751R Group
Section 13 Bus State Controller (BSC)
R01UH0457EJ0301 Rev. 3.01
Page 359 of 1128
Sep 24, 2013
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
Description
0
MPX or SRAM interface is selected by MEMMPX
(Initial value)
1
MPX or SRAM interface is selected by A1MPX and A4MPX