7902 Group User’s Manual
APPENDIX
21-34
Appendix 2. Control registers
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
CS1 control register L (Address 8216)
CS2 control register L (Address 8416)
CS3 control register L (Address 8616)
Area CSj bus cycle select bit 0
(j = 1 to 3)
External data bus width select bit
RDY control bit
(Note 2)
The value is “0” at reading.
Burst ROM access select bit
(Note 3)
Recovery cycle insert select bit
CSj output select bit
(j = 1 to 3)
(Note 4)
RW
—
RW
b7 b6 b5 b4 b3 b2 b1 b0
Notes 1: This bit is fixed to “1” (8-bit width) when Vcc-level voltage is applied to pin BYTE.
2: Valid when the RDY input select bit (bit 2 at 5F16) is “1.”
3: When the external data bus width select bit (bit 2) is “1” or when Vcc-level voltage is applied to pin BYTE, “normal access”
is selected regardless of this bit’s value.
4: This bit’s value is invalid in the single-chip mode. (CSj output is disabled.)
0 : 16-bit width
1 : 8-bit width
(Note 1)
0 : RDY control is valid.
1 : RDY control is invalid.
0 : Normal access
1 : Burst ROM access
0 : No recovery cycle is inserted with area CSj selected.
1 : Recovery cycle is inserted with area CSj selected.
0 : CSj output is disabled. (P45 to P47 function as
programmable I/O port pins.)
1 : CSj output is enabled. (P45 to P47 function as pin CSj.)
0
1
0
1
0
Bit name
Bit
Function
At reset
R/W
0 0 : 1
φ + 1φ
0 1 : 1
φ + 2φ
1 0 : 1
φ + 3φ
1 1 : 2
φ + 2φ
b0
b1
0 0 : 2
φ + 3φ
0 1 : 2
φ + 4φ
1 0 : 3
φ + 3φ
1 1 : 3
φ + 4φ
b0
b1
(Area CSj bus cycle select
bit 1 = 0)
(Area CSj bus cycle select
bit 1 = 1)
CS1 control register H (Address 8316)
Area CS1 block size select bits
Area CS1 bus cycle select bit 1
The value is “0” at reading.
Fix this bit to “0.”
The value is “0” at reading.
Area CS1 setting mode select bit
0 0 0 : 0 byte (Area CS1 is invalid.)
0 0 1 : 128 Kbytes
0 1 0 : 256 Kbytes
0 1 1 : 512 Kbytes
1 0 0 : 1 Mbytes
1 0 1 : 2 Mbytes
1 1 0 : 4 Mbytes
1 1 1 : 8 Mbytes
b2 b1 b0
b7 b6 b5 b4 b3 b2 b1 b0
0 : Mode 0 (A block can be set to 16-Mbyte space.)
1 : Mode 1 (A block can be set to bank 0.)
(Mode 0)
0 byte (Area CS1 is invalid.)
Do not select.
4 Kbytes
8 Kbytes
Do not select.
0
RW
—
RW
—
RW
Bit name
Bit
Function
At reset
R/W
(Mode 1)
The combination of this bit and the area CS1 bus
cycle select bit 0 selects the bus cycle.
0 : 1
φ + 1φ, 1φ + 2φ, 1φ + 3φ, or 2φ + 2φ
1 : 2
φ + 3φ, 2φ + 4φ, 3φ + 3φ, or 3φ + 4φ
0
Reference
3-15
3-5
3-15
Reference
3-16