X68C64 Datasheet, PDF (2/12 Pages) Xicor Inc. – E2 Micro-Peripheral

X68C64
PIN DESCRIPTIONS
Address/Data (A/D₀–A/D₇)
Multiplexed low-order addresses and data. The ad-
dresses flow into the device while AS is HIGH. After AS
transitions from a HIGH to LOW the addresses are
latched. Once the addresses are latched these pins
input data or output data depending on E, R/W, and CE.
Addresses (A₈–A₁₂)
High order addresses flow into the device when AS is
HIGH and are latched when AS goes LOW.
Chip Enable (CE)
The Chip Enable input must be HIGH to enable all read/
write operations. When CE is LOW and AS is LOW, the
X68C64 is placed in the low power standby mode.
Enable (E)
When used with a MC6801 or MC6803, the E input is tied
directly to the E output of the microcontroller.
Read/Write (R/W)
When used with a MC6801 or MC6803, the R/W input is
tied directly to the R/W output of the microcontroller.
Address Strobe (AS)
Addresses flow through the latches to address decoders
when AS is HIGH and are latched when AS transitions
from a HIGH to LOW.
Device Select (SEL)
Must be connected to V_SS.
Write Control (WC)
The Write Control allows external circuitry to abort a
page load cycle once it has been initiated. This input is
useful in applications in which a power failure or proces-
sor RESET could interrupt a page load cycle. In this
case, the microcontroller might drive all signals HIGH,
causing bad data to be latched into the E²PROM. If the
Write Control input is driven HIGH (before t_TBLC Max)
after Read/Write (R/W) goes HIGH, the write cycle will
be aborted.
When WC is LOW (tied to V_SS) the X68C64 will be
enabled to perform write operations. When WC is HIGH
normal read operations may be performed, but all at-
tempts to write to the device will be disabled.
PIN CONFIGURATION
DIP/SOIC
NC
A12
NC
NC
WC
SEL
A/D0
A/D1
A/D2
A/D3
A/D4
VSS
1
24
2
23
3
22
4
21
5
20
6
19
X68C64
7
18
8
17
9
16
10
15
11
14
12
13
VCC
R/W
AS
A8
A9
A11
E
A10
CE
A/D7
A/D6
A/D5
3868 FHD F01.1
PIN NAMES
Symbol
AS
A/D0–A/D7
A₈–A₁₂
E
R/W
CE
WC
SEL
V_SS
VCC
NC
Description
Address Strobe
Address Inputs/Data I/O
Address Inputs
Enable Input
Read/Write Input
Chip Enable
Write Control
Device Select—Connect to VSS
Ground
Supply Voltage
No Connect
3868 PGM T01.1
2