AM29BDD160G AMD [Advanced Micro Devices], AM29BDD160G Datasheet - Page 42

• Manufacturer Part Number: AM29BDD160G
• Description: 16 Megabit (1 M x 16-bit/512 K x 32-Bit), CMOS 2.5 Volt-only Burst Mode, Dual Boot, Simultaneous Read/Write Flash Memory
• Manufacturer: AMD [Advanced Micro Devices]

SecSi Sector Entry Command
The SecSi Sector Entry command enables the SecSi
(OTP) sector to overlay the 8 KB outermost sector in
the small (25%) bank. The SecSi sector overlays
00000h–0003Fh for the top boot block configuration
and 7FFC0h–7FFFFh for the bottom boot block confi-
uration. Address range 00040h–007FFh for the top
boot block and 7F800h–7FFBFh return invalid data
when addressed with the SecSi sector enabled. The
following commands are permitted after issuing the
SecSi Sector Entry command:
1. Autoselect
2. Password Program (x16 and x32)
3. Password Verify
4. Password Unlock (x16 and x32)
5. Read/Reset
6. Program
7. Chip and Sector Erase
8. SecSi Sector Protection Bit Program
9. PPB Program
10.All PPB Erase
11. PPB Lock Bit Set
12.DYB Write
13.DYB/PPB/PPB Lock Bit Verify
14.Security Reset
15.Configuration Register Write
16.Configuration Register Read
The following commands are unavailable when the
SecSi sector is enabled. Issuing the following com-
mands while the SecSi sector is enabled results in
the command being ignored.
1. Unlock Bypass
2. CFI
3. Accelerated Program
4. Program and Sector Erase Suspend
5. Program and Sector Erase Resume
The SecSi Sector Entry command is allowed when
the device is in either program or erase suspend
modes. If the SecSi sector is enabled, the program
or erase suspend command is ignored. This prevents
resuming either programming or erasure on the
SecSi sector if the overlaid sector was undergoing
programming or erasure. The host system must
ensure that the device resume any suspended
program or erase operation after exiting the
SecSi sector.
Executing any of the PPB program/erase commands,
or Password Unlock command results in the small
bank (25% bank) returning the status of these oper-
ations while they are in progress, thus making the
SecSi sector unavailable for reading. If the SecSi
sector is enabled while the DYB command is issued,
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Am29BDD160G
the DYB for the overlaid sector is NOT updated.
Reading the DYB status using the PPB Lock Bit/DYB-
DYB verify command when the SecSi sector is
enabled returns invalid data.
Password Program Command
The Password Program Command permits program-
ming the password that is used as part of the
hardware protection scheme. The actual password is
64-bits long. Depending upon the state of the
WORD# pin, multiple Password Program Commands
are required. For a x16 bit data bus, 4 Password Pro-
gram comman ds are required to program the
password. For a x32 bit data bus, 2 Password Pro-
gram commands are required. The user must enter
the unlock cycle, password program command (38h)
and the program address/data for each portion of
the password when programming. There are no pro-
visions for entering the 2-cycle unlock cycle, the
password program command, and all the password
data. There is no special addressing order required
for programming the password. Also, when the pass-
word is undergoing programming, Simultaneous
Operation is disabled. Read operations to any mem-
ory location will return the programming status.
Once programming is complete, the user must issue
a Read/Reset command to return the device to nor-
mal operation. Once the Password is written and
verified, the Password Mode Locking Bit must be set
in order to prevent verification. The Password Pro-
gram Command is only capable of programming
“0”s. Programming a “1” after cell is programmed as
a “0” results in a time-out by the Embedded Program
Algorithm™ with the cell remaining as a “0”. The
password is all F’s when shipped from the factory. All
64-bit password combinations are valid as a pass-
word.
Password Programming is permitted if the SecSi sec-
tor is enabled.
Password Verify Command
The Password Verify Command is used to verify the
Password. The Password is verifiable only when the
Password Mode Locking Bit is not programmed. If
the Password Mode Locking Bit is programmed and
the user attempts to verify the Password, the device
will always drive all F’s onto the DQ data bus.
The Password Verify command is permitted if the
SecSi sector is enabled. Also, the device will not op-
erate in Simultaneous Operation when the Password
Verify command is executed. Only the password is
returned regardless of the bank address. The lower
two address bits (A0:A-1) are valid during the Pass-
word
Password Protection Mode Locking Bit
Program Command
The Password Protection Mode Locking Bit Program
Command programs the Password Protection Mode
Locking Bit, which prevents further verifies or up-
dates to the Password. Once programmed, the
Password Protection Mode Locking Bit cannot be