36

Shutter_Max_Bound_Lower

Address: 0x1D

Access: Read/Write

Reset Value: 0x8C (before SROM download)

0x00 (after SROM download)

Bit

7

6

5

4

3

2

1

0

Field

Shutter_Max_Bound_Upper

Address: 0x1E

Access: Read/Write

Reset Value: 0x20

Bit

7654

3

2

1

0

Field

Data Type: 16-bit unsigned integer.

USAGE: This value sets the maximum allowable shutter value when operating in automatic mode. Units are clock

cycles. Since the automatic frame rate function is based on shutter value, the value in these registers can limit the

range of the frame rate control. To read from the registers, read Upper first followed by Lower. To write to the registers,

write Lower first, followed by Upper, then execute a write to the Frame_Period_Max_Bound_Upper and Lower

registers. To set the shutter manually, disable the AGC via the Extended_Config register and write the desired value

to these registers.

Reading this register will return the most recent value that was written to it. However, the value will take effect only

after a write to the Frame_Period_Max_Bound_Upper and Lower registers. After writing to Frame_Period_Max_Bound_

Upper, wait at least two frame times before writing to Shutter_Max_Bound_Upper or Lower again. The “Busy” bit in the

Extended_Config register may be used in lieu of a timer to determine when it is safe to write. See the Extended_Config

register for more details.

In addition, the three bound registers must also follow this rule when set to non-default values:

Frame_Period_Max_Bound ≥ Frame_Period_Min_Bound + Shutter_Max_Bound.

SROM_ID

Address: 0x1F

Access: Read

Reset Value: 0x00

Bit

7

6

5

4

3

2

1

0

Field

Data Type:8-Bit unsigned integer.

USAGE: Contains the revision of the downloaded Shadow ROM firmware. If the firmware has been successfully down-

loaded and the chip is operating out of SROM, this register will contain the SROM firmware revision, otherwise it will

contain 0x00.

Note: The IC hardware revision is available by reading the Revision_ID register (register 0x01).

Reserved

Address: 0x20 – 0x3C

PixArt Imaging Inc.