Preliminary

CAT35C804A

7

Doc. No. 25043-00 2/98

also go to the high impedance state if an error condition

is detected. In the event an ENABLE BUSY instruction

has not been sent, a READ STATUS register instruction

can be executed. This also tells the user whether the part

is in a program/erase cycle or an error condtion. When

the device is in a program/erase cycle it will output an

8-bit status word. If it does not, it is in an error condition.

PE

The Parity Enable pin is a TTL compatible input. If the PE

pin is set HIGH, the device will be configured to commu-

nicate using even parity, and if the pin is set LOW, it will

use no parity. In this case, instructions or data that

include parity bits will not be interpreted correctly. Note:

The PE input is internally pulled down to GND (i.e.

default = no parity). As with all CMOS devices, CS, CLK

and DI inputs must be connected to either HIGH or LOW,

and not left floating.

ERR

The Error indication pin is an open drain output. If either

an instruction or parity error exists, the ERR pin will

output a “0” until the device is reset. This can be done by

pulsing CS LOW.

Figure 6. Read Timing (x8 Format)

CS

DI

HIGH-Z

DO

OP0–OP7

OP CODE

A8–A15

ADDRESS

A0–A7

ADDRESS

D0–D7

DATA

CLK

VCC

35C804 F09

Figure 7. Read Timing (x16 Format)

CS

DI

HIGH-Z

DO

OP0–OP7

OP CODE

A0–A7

ADDRESS

D8–D15

DATA

CLK

VCC

D0–D7

DATA

HIGH-Z

35C804 F10