LM9830 datasheet(19/45 Pages) NSC

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DIGITAL PIXEL RATE OFFSET AND GAIN SETTINGS

Multiplier Gain Range

Smaller gain ranges provide finer control.

Larger gain ranges correct for larger shading

errors.

0 0 1.5:1 (33%)

0 1 2.0:1 (50%)

1 0 3.0:1 (66%)

1 1 Bypass Multiplier

Offset/Gain data format

6 bits offset/10 bits gain

8 bits offset/8 bits gain

Multiplier Coefficient Source

Configuration Register 3F (Fixed)

External SRAM

Offset Coefficient Source

Configuration Register 40 and 41 (Fixed)

External SRAM

Fixed Offset Coefficient

n nnnnnnn

Fixed Offset to use for calibration - 2MSBs are

assumed to be 0 if using 6 bit offset format

Fixed Multiplier Coefficient - MSB

n n Fixed Gain to use for calibration - 2LSBs are assumed

to be 0 if using 8 bit gain format

Fixed Multiplier Coefficient - LSB

n nnnnnnn

PARALLEL PORT SETTINGS

Communication Mode

(for reading data from any of the LM9830’s

registers)

Note: This register must be set

appropriately before data can be read

from the LM9830!

0 8 bit Bidirectional/EPP

1 4 bit Nibble

Parallel Port Output Driver Current

(IOL and IOH can be used to calculate rise

and fall times into the load capacitance:

rise/fall time approximately equals 5V*C/i)

IOL = 5mA, IOH = -6mA

IOL = 7mA, IOH = -9mA

IOL = 9mA, IOH = -12mA

IOL = 15mA, IOH = -21mA

EXTERNAL SRAM SETTINGS

External SRAM Size

0 0 64 kbytes (not recommended for 600dpi scanners)

0 1 128 kbytes

1 0 256 kbytes

11 N/A

SRAM Interface Output Driver Current

(IOL and IOH can be used to calculate rise

and fall times into the load capacitance:

rise/fall time approximately equals 5V*C/i)

IOL = 3.5mA, IOH = -4mA

IOL = 6mA, IOH = -7.5mA

IOL = 12mA, IOH = -17mA

IOL = 21mA, IOH = -32mA

SRAM Bandwidth (8 Bit Data Mode)

8 slot mode should always be used to

maximize performance. If the external

SRAM is to slow to meet the tRD SETUP

requirement, the slower 4 SRAM

accesses/ADC clock mode may be used.

4 SRAM accesses/ADC clock

8 SRAM accesses/ADC clock

(fMCLK must be 25MHz or lower)

Scanning Duplex (10/12 bit Data Mode)

Full Duplex mode should always be used to

maximize scan speed. If the external SRAM

is to slow to meet the tRD SETUP requirement,

the slower Half Duplex mode may be used.

Full Duplex- Can transmit data while scanning

(fMCLK must be 25MHz or lower)

Half Duplex - Can only transmit data when buffer is full

or scan has been stopped

Address

Function

Value

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