AM28F020A Advanced Micro Devices, AM28F020A Datasheet - Page 10

• Manufacturer Part Number: AM28F020A
• Description: 2 Megabit (256 K x 8-Bit) CMOS 12.0 Volt/ Bulk Erase Flash Memory with Embedded Algorithms
• Manufacturer: Advanced Micro Devices

READ-ONLY MODE
When V
is inactive. The device can either read array or autose-
lect data, or be standby mode.
Read
The device functions as a read only memory when V
< V
must be satisfied in order to output data. CE# controls
power to the device. This pin should be used for spe-
cific device selection. OE# controls the device outputs
and should be used to gate data to the output pins if a
device is selected.
Address access time t
stable addresses to valid output data. The chip enable
access time t
stable CE# to valid data at the output pins. The output
enable access time is the delay from the falling edge of
OE# to valid data at the output pins (assuming the ad-
dresses have been stable at least t
Standby Mode
The device has two standby modes. The CMOS
standby mode (CE# input held at V
sumes less than 100 µA of current. TTL standby mode
(CE# is held at V
to less than 1 mA. When in the standby mode the out-
puts are in a high impedance state, independent of the
OE# input.
If the device is deselected during erasure, program-
ming, or program/erase verification, the device will
draw active current until the operation is terminated.
10
Type
Manufacturer Code
Device Code
CC
+ 2 V. The device has two control functions. Both
PP
is less than V
CE
is the delay from stable addresses and
IH
) reduces the current requirements
ACC
CC
+ 2 V, the command register
is equal to the delay from
ACC
Table 2. (Am28F020A Auto Select Code
CC
- t
OE
0.5 V), con-
).
Am28F020A
PP
Output Disable
Output from the device is disabled when OE# is at a
logic high level. When disabled, output pins are in a
high impedance state.
Auto Select
Flash memories can be programmed in-system or in a
standard PROM programmer. The device may be sol-
dered to the circuit board upon receipt of shipment and
programmed in-system. Alternatively, the device may
initially be programmed in a PROM programmer prior
to soldering the device to the board.
The Auto select mode allows the reading out of a binary
code from the device that will identify its manufacturer and
type. This mode is intended for the purpose of automati-
cally matching the device to be programmed with its cor-
responding programming algorithm. This mode is
functional over the entire temperature range of the device.
Programming In A PROM Programmer
To activate this mode, the programming equipment
must force V
identifier bytes may then be sequenced from the device
outputs by toggling address A0 from V
address lines must be held at V
less than or equal to V
select mode. Byte 0 (A0 = V
turer code and byte 1 (A0 = V
code. For the device the two bytes are given in the table
2 of the device data sheet. All identifiers for manufac-
turer and device codes will exhibit odd parity with the
MSB (DQ7) defined as the parity bit.
ID
(11.5 V to 13.0 V) on address A9. Two
CC
+ 2.0 V while using this Auto
IL
) represents the manufac-
V
A0
V
IH
IH
IL
) the device identifier
IL
, and V
IL
to V
PP
IH
(HEX)
Code
. All other
01
29
must be