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May 21, 2004 S29PL127_064_032J_00_A1
S29PL127J/S29PL064J/S29PL032J for MCP
29
Prelimin ary
Device Bus Operations
This section describes the requirements and use of the device bus operations,
which are initiated through the internal command register. The command register
itself does not occupy any addressable memory location. The register is a latch
used to store the commands, along with the address and data information
needed to execute the command. The contents of the register serve as inputs to
the internal state machine. The state machine outputs dictate the function of the
device.
Table 1 lists the device bus operations, the inputs and control levels they
require, and the resulting output. The following subsections describe each of
these operations in further detail.
Legend: L= Logic Low = VIL, H = Logic High = VIH, VID = 11.5-12.5 V, VHH = 8.5-9.5 V, X = Don’t Care, SA =
Sector Address, AIN = Address In, DIN = Data In, DOUT = Data Out
Notes:
1. The sector protect and sector unprotect functions may also be implemented via programming equipment. See the
2. WP#/ACC must be high when writing to upper two and lower two sectors.
Requirements for Reading Array Data
To read array data from the outputs, the system must drive the OE# and appro-
priate CE# pins. OE# is the output control and gates array data to the output
pins. WE# should remain at VIH.
The internal state machine is set for reading array data upon device power-up,
or after a hardware reset. This ensures that no spurious alteration of the memory
content occurs during the power transition. No command is necessary in this
mode to obtain array data. Standard microprocessor read cycles that assert valid
addresses on the device address inputs produce valid data on the device data
outputs. Each bank remains enabled for read access until the command register
contents are altered.
ICC1 in the DC Characteristics table represents the active current specification for
reading array data.
Random Read (Non-Page Read)
Address access time (tACC) is equal to the delay from stable addresses to valid
output data. The chip enable access time (tCE) is the delay from the stable ad-
dresses and stable CE# to valid data at the output inputs. The output enable
Table 1. PL127J Device Bus Operations
Operation
CE#
OE#
WE#
RESET#
WP#/ACC
Addresses
(Amax–A0)
DQ15–
DQ0
Read
L
H
X
AIN
DOUT
Write
L
H
L
H
AIN
DIN
Standby
VIO±
0.3 V
X
VIO ±
0.3 V
X
High-Z
Output Disable
L
H
X
High-Z
Reset
X
L
X
High-Z
Temporary Sector Unprotect (High Voltage)
X
VID
X
AIN
DIN