APPLICATION NOTE FOR UPGRADING FROM THE AT49BV6416(T) TO THE AT49BV642D(T)
The purpose of this application note is to aid customers in converting from the AT49BV6416(T) to the
AT49BV642D(T).
The AT49BV6416(T) and the AT49BV642D(T) both operate in the word (x16) configuration. The
AT49BV6416(T) is divided into four planes, and the AT49BV642D(T) is a single plane part. The user
should be aware of the following differences in the operation of a single plane and a multiple plane part –
A multi-plane part, like the AT49BV6416(T), allows a concurrent read operation in any plane that is not
being programmed or erased. However, a single plane part does not permit concurrent read operations in
hardware. This operation can be implemented using the erase-suspend/resume or programsuspend/resume commands.
With a single plane device, a read from I/O7 and I/O6 during a programming or an erase operation will
give status information. However, when using a multi plane part, a read from I/O7 and I/O6 will only
provide status information if the read is performed in the same plane that the erase or programming
operation is occurring in. When a read from I/O7 and I/O6 is performed on a plane in which the
programming or an erase operation is not taking place, valid data will be read.
When resuming a suspended erase operation from a multi plane device, the erase resume command
must be issued to an address within the plane whose erase was suspended. With a single plane device, it
is not necessary to provide plane information when doing an erase resume operation.
Device Architecture and Sectoring Comparison
The AT49BV6416(T) and the AT49BV642D(T) have identical sector maps.
Pinout Comparison
The AT49BV6416(T) and the AT49BV642D(T) are both offered in a 48-pin TSOP package. The
AT49BV642D(T) is pinout compatible with the AT49BV6416(T). The only difference in pinout is that the
AT49BV6416(T) offers a WP/ pin while the location of this pin is a no connect on the AT49BV642D(T).
Since, any voltage can be applied to a no connect pin, no board changes are necessary in converting
from the AT49BV6416(T) to the AT49BV642D(T).
A Comparison of Device READ Operations
The AT49BV6416(T) supports asynchronous and page read operations. The page mode read is not
available on the AT49BV642D(T). All the other read operations are the same for both the parts.
1 of 3
Differences in the Device ID’s
As shown in the table below, during the product ID entry command of the AT49BV6416(T), a plane
address is required during the third and fourth bus cycles. On the AT49BV642D(T), these addresses are
555H and 00000H or 00001H respectively. To manage these differences, we recommend using address
555H during the third bus cycle, addresses 00000H, 000001H during the fourth bus cycle to read the
manufacturer ID and the device ID respectively.
Device
AT49BV6416(T)
AT49BV642D(T)
AT49BV6416
AT49BV6416T
AT49BV642D
AT49BV642DT
Command
Sequence
Manufacturer
Code Entry
Manufacturer
Code Entry
Device Code
Entry
Device Code
Entry
Device Code
Entry
Device Code
Entry
1st Bus Cycle
2nd Bus Cycle
3rd Bus Cycle
Addr
Data
Addr
Data
Addr
Data
Addr
Data
3
555
AA
AAA
55
PA+00555
90
PA+00000h
001FH
3
555
AA
AAA
55
555
90
00000h
001FH
3
555
AA
AAA
55
PA+00555
90
PA+00001h
00D6H
3
555
AA
AAA
55
PA+00555
90
PA+00001h
00D2H
3
555
AA
AAA
55
555
90
00001h
01D6H
3
555
AA
AAA
55
555
90
00001h
01D2H
Bus
Cycles
4th Bus Cycle
A Comparison of the Sector Protection Options
The AT49BV6416(T) supports two sector protection modes, the Softlock and the Hardlock. The
AT49BV642D(T) supports only the hardlock protection mode (referred to as sector lockdown in the
datasheet) which works without using the WP/ pin. At power-up and reset, all sectors of the
AT49BV6416(T) have their softlock protection mode enabled while on the AT49BV642D(T) all sectors are
unlocked.
Sector Unlock
The sectors of the AT49BV6416(T) can be unlocked using a two-bus cycle command. This command is
not available on the AT49BV642D(T). To unlock the sectors of the AT49BV642D(T), the device must be
reset or power cycled. After power-up or reset, the contents of a sector that is locked down can be erased
and reprogrammed.
2 of 3
Comparison of Program, Erase, and Unlock Commands
Dual-Word Program
As shown in the table below, when using the dual-word program command, the data programmed during
the third bus cycle is different between the AT49BV6416(T) and the AT49BV642D(T). To manage this
difference, the user should program data E0 during the third bus cycle when using the dual-word program
command on the AT49BV642D(T).
Device
AT49BV6416(T)
AT49BV642D(T)
Command
Sequence
Dual-Word
Program
Dual-Word
Program
1st Bus Cycle
2nd Bus Cycle
3rd Bus Cycle
4th Bus Cycle
5th Bus Cycle
Addr
Data
Addr
Data
Addr
Data
Addr
Data
Addr
Data
3
555
AA
AAA
55
555
A1
Addr0
DIN0
Addr1
DIN1
3
555
AA
AAA
55
555
E0
Addr0
DIN0
Addr1
DIN1
Bus
Cycles
Plane Erase
The AT49BV6416(T) supports the plane erase command sequence. This command is not available on the
AT49BV642D(T). The sector erase command is available on the AT49BV642D(T) and can be used to
erase individual sectors, or the chip erase command can be used to erase the entire memory.
Comparison Of Programming, Locking and Status of Block B of the Protection Register
For the AT49BV6416(T), the address used during the fourth bus cycle of the programming, the locking
and the read status of block B of the protection register is different for the top and the bottom boot block
devices. This address is identical for the top and the bottom boot block devices of the AT49BV642D(T).
To manage these differences, on the AT49BV642D(T), during the fourth bus cycle we recommend using
an address between 000081H-000080H when programming , address 80H when locking and reading the
status of block B of the protection register.
3 of 3