19

SROM Download

This function is used to load the

PixArt Imaging

supplied firmware file contents into the ADNS-3090. The

firmware file is an ASCII text file with each 2-character

byte (hexadecimal representation) on a single line.

This mode is activated by the following steps:

1. Perform hardware reset by toggling the RESET pin

2. Write 0x44 to register 0x20

3. Write 0x07 to register 0x23

4. Write 0x88 to register 0x24

5. Wait at least 1 frame period

6. Write 0x18 to register 0x14 (SROM_Enable register)

7. Begin burst mode write of data file to register 0x60

(SROM_Load register)

After the first data byte is complete, the SROM or micro-

controller must write subsequent bytes by presenting

the data on the MOSI line and driving SCLK at the normal

Figure 23. SROM download burst mode

bytes as shown. After the download is complete, the

to terminate burst mode. The serial port is not available

for use until it is reset with NCS, even for a second burst

transmission.

PixArt Imaging recommends reading the SROM_ID

register to verify that the download was successful. In

addition, a self-test may be executed, which performs a

CRC on the SROM contents and reports the results in a

register. The test is initiated by writing a particular value

to the SROM_Enable register; the result is placed in the

Data_Out register. See those register descriptions for

more details.

PixArt Imaging provides the data file for download;

the file size is 1986 data bytes. The chip will ignore any

additional bytes written to the SROM_Load register after

the SROM file.

NCS

address

key data

address

byte 0

MOSI

SCLK

SROM_Enable reg write

SROM_Load reg write

exit burst mode

enter burst

mode

≥4μs

byte 1

byte 1985

>120ns

address

soonest to read SROM_ID

3 reg writes, see text

period

≥40μs

≥10μs

≥10μs

≥10μs

≥100μs

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PixArt Imaging Inc.

PixArt Imaging Inc.