X68257 Datasheet, PDF(3/14 Page) Xicor Inc.

English

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

X68257 Datasheet, PDF (3/14 Pages) Xicor Inc. – E2 Micro-Peripheral

◁

X68257

PRINCIPLES OF OPERATION

The X68257 is a highly integrated peripheral device for

a wide variety of single-chip microcontrollers. The X68257

provides 32K-bytes of 5V E2PROM which can be used

either for program storage, data storage, or a combina-

tion of both, in systems based upon Von Neumann

(68XX) architectures. The X68257 incorporates 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 X68257 are configured such

that it is possible to directly connect them to the proper

interface signals of the appropriate single-chip micro-

controller.

The X68257 features the industry standard 5V E2PROM

characteristics such as byte or page mode write and

Toggle Bit Polling.

Typical Application

30 XTAL

29 EXTAL

39 RESET

41 IRQ

40 XIRQ

8 PA0

7 PA1

6 PA2

5 PA3

4 PA4

3 PA5

2 PA6

1 PA7

25 MODA

24 MODB

42 PD0

43 PD1

44 PD2 MISO

45 PD3 MOSI

46 PD4 SCK

47 PD5 SS

68HC11

DEVICE OPERATION

Motorola 68XX operation requires the microcontroller

AS, E, and R/W outputs to be tied to the X68257 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 the 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 is 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

present at A/D0âA/D7 will be strobed into the X68257 on

the HIGH to LOW transition of E.

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

PB5 11

PB6 10

PB7 9

AS 26

R/W 28

E 27

PE0 17

PE1 18

PE2 19

PE3 20

VRH 22

VRL 21

11 A/D0

12 A/D1

12 A/D2

15 A/D3

16 A/D4

17 A/D5

18 A/D6

19 A/D7

25 A8

24 A9

21 A10

23 A11

2 A12

26 A13

1 A14

5 CE

3 AS

27 R/W

22 E

X68257

VCC

SEL 4

6539 ILL F03.2

▷