
22
Motion
Access: Read/Write
Address: 0x02
Reset Value: 0x00
Bit
7
6
5
4
3
2
1
0
Field
MOT
PIXRDY
PIXFIRST
OVF
LP_VALID
FAULT
Reserved
Reserved
Data Type
: Bit field.
USAGE: Register 0x02 allows the user to determine if motion has occurred since the last time it
was read. If the MOT bit is set, then the user should read registers 0x03 and 0x04 to get the
accumulated motion. Read this register before reading the Delta_X and Delta_Y registers.
Writing anything to this register clears the MOT and OVF bits, Delta_X and Delta_Y registers. The
written data byte is not saved.
Internal buffers can accumulate more than eight bits of motion for X or Y. If either one of the
internal buffers overflows, then absolute path data is lost and the OVF bit is set. To clear
theoverflow, write anything to this register.
Check the OVR bit if more than 4" of motion is accumulated without reading it. If bit set, discard
the motion as erroneous. Write anything to this register to clear the overflow condition.
The PIXRDY bit will be set whenever a valid pixel data byte is available in the Pixel_Dump
register. Check that this bit is set before reading from Pixel_Dump. To ensure that the Pixel_Grab
pointer has beenreset to pixel 0,0 on the initial write to Pixel_Grab, check to see if PIXFIRST is
set to high.
NOTE: Agilent recommends that registers 0x02, 0x03 and 0x04 be read sequentially.
Field Name
Description
MOT
Motion since last report
0 = No motion
1 = Motion occurred, data ready for reading in Delta_X and Delta_Y registers
PIXRDY
Pixel Pump data byte is available in Pixel_Dump register
0 = data not available
1 = data available
PIXFIRST
This bit is set when the Pixel_Grab register is written to or when a complete pixel array
has been read, initiating an increment to picel 0,0.
0 = Pixel_Grab data not from pixel 0,0.
1 = Pixel_Grab data is from pixel 0,0.
Motion overflow,
Y and/or
X buffer has overflowed since last report
0 = no overflow
1 = Overflow has occurred
OVF
LP_VALID
Laser Power Settings
0 = register 0x1a and register 0x1f or register 0x1c and register 0x1d do not have
complementary values
1 = laser power is valid
FAULT
Indicates that XY_LASER is shorted to GND or VDD
0 = no fault detected
1 = fault detected