10

www.national.com

Register Listing

Registers in bold boxes are reset to that value on power-up. All register addresses are in hexadecimal. All other numbers are

decimal unless otherwise noted.

Address

Function

D

7

D

6

D

5

D

4

D

3

D

2

D

1

D

0

Value

IMAGE BUFFER (READ ONLY)

00

Pixel (Image) Data

nnn nnnnnOne byte of image data.

STATUS REGISTERS (READ ONLY)

01

Image Data Available In Buffer

nnn nnnnn

n*2 (256k x 16 DRAM) or n*8 (1M x 16 DRAM)

kilobytes of image data is available

02

PAPER SENSE 1 State

read clears bit if edge sensitive input.

0False

1True

PAPER SENSE 2 State

read clears bit if edge sensitive input.

0False

1True

MISC I/O 1 State

read clears bit if edge sensitive input.

0False

1True

MISC I/O 2 State

read clears bit if edge sensitive input.

0False

1True

MISC I/O 3 State

read clears bit if edge sensitive input.

0False

1True

MISC I/O 4 State

read clears bit if edge sensitive input.

0False

1True

MISC I/O 5 State

read clears bit if edge sensitive input.

0False

1True

MISC I/O 6 State

read clears bit if edge sensitive input.

0False

1True

DATAPORT REGISTERS

03

DataPort Target

0 0 Offset Coefficient Data

0 1 Gain Coefficient Data

1 0 Gamma Lookup Table

11N/A

DataPort Target Color

00

Red

01

Green

10

Blue

11

N/A

Pause (Read Only)

This bit indicates whether or not the scanner

is currently paused due to a buffer full

condition.

0Normal State

1

The scanner is currently in the pause/reverse cycle.

DRAM Test

0

Normal Operation

1

DRAM Test mode

04

DataPort Address - MSB

R

/

W

a aaaaa

Address of location to be read/written to.

a = 0 to 4095 for gamma tables,

0 to 16383 for Offset and Gain Coefficient Data

Addresses greater than these are illegal.

Bit D6 of register 4 indicates whether next operation

will be a Read (D6=1) or a Write (D6=0).

05

DataPort Address - LSB

aaa aaaaa

06

DataPort

nnn nnnnn

Data to be read from or written to the address of the

currently selected Dataport Target. The DataPort

Address is automatically incremented whenever one

(gamma data) or two (Gain/Offset Data) bytes are

read from or written to this register.