X86C64 Datasheet, PDF (3/12 Pages) Xicor Inc. – E2 Micro-Peripheral

X86C64
PRINCIPLES OF OPERATION
The X86C64 is a highly integrated peripheral device for
a wide variety of single-chip microcontrollers. The
X86C64 provides 8K bytes of 5-volt E²PROM which can
be used either for Program Storage, Data Storage or a
combination of both in systems based upon Von
Neumann (86XX) architectures. The X86C64 incorpo-
rates the interface circuitry normally needed to decode
the control signals and demultiplex the Address/Data
bus to provide a “ Seamless” interface.
The interface inputs on the X86C64 are configured such
that it is possible to directly connect them to the proper
interface signals of the appropriate single-chip
microcontroller.
The X86C64 is internally organized as two independent
planes of 4K bytes of memory with the A₁₂ input select-
ing which of the two planes of memory are to be
accessed. While the processor is executing code out of
one plane, write operations can take place in the other
plane, allowing the processor to continue execution of
code out of the X86C64 during a byte or page write to the
device.
The X86C64 also features an advanced implementation
of the Software Data Protection scheme, called Block
Protect, which allows the device to be broken into 8
independent sections of 1K bytes. Each of these sec-
tions can be independently enabled for write operations;
thereby allowing certain sections of the device to be
secured so that updates can only occur in a controlled
environment (e.g. in an automotive application, only at
an authorized service center). The desired set-up con-
figuration is stored in a nonvolatile register, ensuring the
configuration data will be maintained after the device is
powered down.
The X86C64 also features a Write Control input (WC),
which serves as an external control over the completion
of a previously initiated page load cycle.
The X86C64 also features the industry standard 5-volt
E²PROM characteristics such a byte or page mode write
and toggle-bit polling.
DEVICE OPERATION
Zilog Z8 operation requires the microcontroller’s AS, DS
and R/W outputs tied to the X86C64 AS, DS and
R/W inputs respectively.
The rising edge of AS will latch the addresses for both a
read and write operation. The state of R/W output
determines the operation to be performed, with the DS
signal acting as a data strobe.
If R/W is HIGH and CE HIGH (read operation) data will
be output on A/D₀–A/D₇ after DS transitions LOW. If
R/W is LOW and CE is HIGH (write operation) data
presented at A/D₀–A/D₇ will be strobed into the X86C64
on the LOW to HIGH transition of DS.
Typical Application
2 _XTAL
3 _EXTAL
21
P10
22
P11
23
P12
24
P13
25
P14
26
P15
27
P16
28
P17
13
P00
14
P01
15
P02
16
P03
17
P04
20
P07
9
AS
8
DS
7
R/W
Z8
24
7
A/D0
8
A/D1
9
A/D2
10
A/D3
11
A/D4
13
A/D5
14
A/D6
15
A/D7
21
A8
20
A9
17
A10
19
A11
2
A12
16
CE
5
WC
22
AS
18
DS
23
R/W
6
SEL
VCC
VSS
X86C64
12
3819 FHD F03
3