SH7206 Datasheet, PDF (235/1188 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series

Section 8 Bus State Controller (BSC)
8.4.2 CSn Space Bus Control Register (CSnBCR) (n = 0 to 8)
CSnBCR is a 32-bit readable/writable register that specifies the function of each area, the number
of idle cycles between bus cycles, and the bus width. This register is initialized to H'36DB0x00 by
a power-on reset and retains the value by a manual reset and in software standby mode.
Do not access external memory other than area 0 until CSnBCR initial setting is completed.
Idle cycles may be inserted even when they are not specified. For details, see section 8.5.12, Wait
between Access Cycles.
Bit: 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
-
IWW[2:0]
IWRWD[2:0]
IWRWS[2:0]
IWRRD[2:0]
IWRRS[2:0]
Initial value: 0
0
1
1
0
1
1
0
1
1
0
1
1
0
1
1
R/W: R R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W
Bit: 15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
-
TYPE[2:0]
-
BSZ[1:0]
-
-
-
-
-
-
-
-
-
Initial value: 0
0
0
0
0
1* 1* 0
0
0
0
0
0
0
0
0
R/W: R R/W R/W R/W R R/W R/W R
R
R
R
R
R
R
R
R
Note: * CSnBCR samples the external pins (MD2 and MD0) that specify the bus width at power-on reset.
Bit
Bit Name
31

30 to 28 IWW[2:0]
Initial
Value
0
011
R/W Description
R
Reserved
This bit is always read as 0. The write value should
always be 0.
R/W Idle Cycles between Write-Read Cycles and Write-
Write Cycles
These bits specify the number of idle cycles to be
inserted after the access to a memory that is
connected to the space. The target access cycles are
the write-read cycle and write-write cycle.
000: No idle cycle inserted
001: 1 idle cycle inserted
010: 2 idle cycles inserted
011: 4 idle cycles inserted
100: 6 idle cycles inserted
101: 8 idle cycles inserted
110: 10 idle cycles inserted
111: 12 idle cycles inserted
Rev. 3.00 Jun. 18, 2008 Page 211 of 1160
REJ09B0191-0300