X68C64 Datasheet, PDF(3/12 Page) Xicor Inc.

English

English German Russian Spanish Italian Polish Chinese Japanese Korean French Portuguese	Language :

X68C64 Datasheet, PDF (3/12 Pages) Xicor Inc. – E2 Micro-Peripheral

◁

X68C64

PRINCIPLES OF OPERATION

The X68C64 is a highly integrated peripheral device for

a wide variety of single-chip microcontrollers. The

X68C64 provides 8K bytes of E2PROM which can be

used either for Program Storage, Data Storage, or a

combination of both in systems based upon Von

Neumann (68XX) architectures. The X68C64 incorpo-

rates the interface circuitry normally needed to decode

the control signals and demultiplex the Address/Data

bus to provide a âSeamlessâ interface.

The interface inputs on the X68C64 are configured such

that it is possible to directly connect them to the proper

interface signals of the appropriate single-chip

microcontroller.

The X68C64 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 X68C64 during a byte or page write to the

device.

The X68C64 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 X68C64 also features a Write Control input (WC),

which serves as an external control over the completion

of a previously initiated page load cycle.

The X68C64 also features the industry standard

E2PROM characteristics such a byte or page mode

write and Toggle Bit Polling.

DEVICE OPERATION

Motorola 68XX operation requires the microcontrollerâs

AS, E, and R/W outputs tied to the X68C64 AS, E, and

R/W inputs respectively.

The falling 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 E

signal acting as a data strobe.

If R/W is HIGH and CE HIGH (read operation), data will

be output on A/D0âA/D7 after E transitions HIGH. If

R/W is LOW and CE is HIGH (write operation), data

presented at A/D0âA/D7 will be strobed into the X68C64

on the HIGH to LOW transition of E.

Typical Application

XTAL

8 MHz

OSC.

EXTAL

VCC VCC

25 MODA

24 MODB

PC0 31

PC1 32

PC2 33

PC3 34

PC4 35

PC5 36

PC6 37

PC7 38

PB0 16

PB1 15

PB2 14

PB3 13

PB4 12

PB7 9

AS 26

E 27

R/W 28

68HC11A8

7 A/D0 VCC

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 E

23 R/W

6 SEL

VSS

X68C64 12

3868 ILL F03.2

▷