Preliminary information
®
AS29F400
READ codes
Mode
MFR code (Alliance Semiconductor)
×8 T boot
Device code
×8 B boot
×16 T boot
×16 B boot
Sector protection
A17–A12
X
X
X
X
X
Sector address
A6
L
L
L
L
L
L
A1
L
L
L
L
L
H
A0
L
H
H
H
H
L
Code
52h
23h
ABh
2223h
22ABh
01h protected
00h unprotected
Key: L =Low (<V
IL
); H = High (>V
IH
); X =Don’t care; T = top; B = bottom
Command format
Command sequence
Reset/Read
×16
Reset/Read
×8
×16
4
AAAAh
5555h
Required
bus cycles
1
1st bus write cycle
Address
XXXXh
5555h
AAh
2nd bus write cycle
Address
Read
Address
2AAAh
55h
5555h
2AAAh
3rd bus write cycle
Address
Data
4th bus write cycle
Address
Data
5th bus write cycle 6th bus write cycle
Address
Data
Address
Data
Data
F0h
Data
Read Data
5555h
F0h
AAAAh
5555h
01h
Device code
Read Address
Read
Data
2223h
(T)
22ABh (B)
23h (T)
ABh (B)
AutoselectI
D Read
×8
4
AAAAh
AAh
5555h
55h
AAAAh
90h
00h
MFR code
52h
01 = protected
00 = unprotected
Program
Data
2AAAh
AAh
55h
5555h
2AAAh
AAh
55h
5555h
AAAAh
Sector
Address
30h
5555h
10h
×16/×8
XXX02h
Sector protection
×16
Program
×8
×16
Chip Erase
×8
×16
Sector Erase
×8
Sector Erase Suspend
Sector Erase Resume
1
2
3
4
5
6
1
1
6
AAAAh
XXXXh
XXXXh
B0h
30h
6
AAAAh
5555h
AAh
5555h
4
AAAAh
5555h
AAh
5555h
2AAAh
55h
AAAAh
5555h
AAh
5555h
2AAAh
55h
AAAAh
5555h
80h
AAAAh
2AAAh
55h
AAAAh
5555h
80h
AAAAh
5555h
5555h
A0h
Program
Address
5555h
Bus operations defined in "Mode definitions," on page 3.
Reading from and programming to non-erasing sectors allowed in Erase Suspend mode.
Address bit A15 = X = Don’t care for all address commands except Program Address and Sector Address.
Address bit A16 = X = Don’t care for all address commands except Program Address and Sector Address.
Address bit A17 = X = Don’t care for all address commands except Program Address and Sector Address.
System should generate address patterns: ×16 mode - 5555h or 2AAAh to addresses A0–A14; ×8 mode - AAAAh or 5555h to addresses A-1–A14.
5
ALSC [ ALLIANCE SEMICONDUCTOR CORPORATION ]
