Bus operations
M29W320DT, M29W320DB
3.6
Special bus operations
Additional bus operations can be performed to read the Electronic Signature and also to
apply and remove Block Protection. These bus operations are intended for use by
programming equipment and are not usually used in applications. They require V to be
ID
applied to some pins.
3.6.1
3.6.2
Electronic Signature
The memory has two codes, the manufacturer code and the device code, that can be read
to identify the memory. These codes can be read by applying the signals listed in Table 2
and Table 3, Bus Operations.
Block Protect and Chip Unprotect
Each block can be separately protected against accidental Program or Erase. The whole
chip can be unprotected to allow the data inside the blocks to be changed.
Block Protect and Chip Unprotect operations are described in Appendix C: Block Protection.
(1)
Table 2.
Bus Operations, BYTE = V
IL
Data Inputs/Outputs
Address Inputs
DQ15A–1, A0-A20
Operation
E
G
W
DQ14-DQ8
DQ7-DQ0
Bus Read
Bus Write
Output Disable
Standby
VIL
VIL
X
VIL
VIH
VIH
X
VIH Cell Address
Hi-Z
Hi-Z
Hi-Z
Hi-Z
Data Output
Data Input
Hi-Z
VIL Command Address
VIH
X
X
X
VIH
Hi-Z
Read Manufacturer
Code
A0 = VIL, A1 = VIL, A9 = VID,
Others VIL or VIH
VIL
VIL
VIL
VIL
VIH
VIH
Hi-Z
Hi-Z
20h
CAh (M29W320DT)
CBh (M29W320DB)
A0 = VIH, A1 = VIL,
A9 = VID, Others VIL or VIH
Read Device Code
1. X = VIL or VIH
.
(1)
Table 3.
Bus Operations, BYTE = V
IH
Address Inputs
A0-A20
Data Inputs/Outputs
DQ15A–1, DQ14-DQ0
Operation
E
G
W
Bus Read
Bus Write
Output Disable
Standby
VIL
VIL
X
VIL
VIH
VIH
X
VIH Cell Address
Data Output
Data Input
Hi-Z
VIL Command Address
VIH
X
X
X
VIH
Hi-Z
Read Manufacturer
Code
A0 = VIL, A1 = VIL, A9 = VID,
Others VIL or VIH
VIL
VIL
VIL
VIL
VIH
VIH
0020h
22CAh (M29W320DT)
22CBh (M29W320DB)
A0 = VIH, A1 = VIL, A9 = VID,
Others VIL or VIH
Read Device Code
1. X = VIL or VIH
.
16/56
NUMONYX [ NUMONYX B.V ]
