Configuring the VT5363

VT5363

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3.5

EEPROM data format

A 128 byte serial EEPROM is used to hold USB configuration information. The lower 64

bytes hold USB PID, VID and string information as shown in the table below. The upper

bytes may be used to hold special setup information, for example to set the resolution to

400cpi (contact STMicroelectronics for details).

Location 127 in the EEPROM must hold the number 0xAA and is used to detect that an

EEPROM has been fitted. If location 127 does not contain 0xAA the EEPROM contents will

be ignored.

Table 4.

Example EEPROM contents

EEPROM

Location

Contains

Notes

0

VID (LSB)

Vendor ID

(only one VID is stored for all 3 mouse configurations)

1

VID (MSB)

2

PID (LSB)

Product ID for 2 button mouse

3

PID (MSB)

4

PID (LSB)

Product ID for ‘3 button + Z’ mouse

5

PID (MSB)

6

PID (LSB)

Product ID for ‘5 button + Z’ mouse

7

PID (MSB)

8

0x04

Language ID Length

9

0x03

Language ID Type

10

0x09

Language ID (2 bytes)

(0x0904 = US English)

11

0x04

12

0x0C

String ID Length = (number of characters in string *2) + 2

For the example string ‘MOUSE’ this is (2*5)+2 = 12 = 0x0C

13

0x03

String ID Type

14

0x4D

ASCII code for first character of String (example for ‘M’)

15

0x4F

ASCII code for first character of String (example for ‘O’)

16

0x55

ASCII code for first character of String (example for ‘U’)

17

0x53

ASCII code for first character of String (example for ‘S’)

18

0x45

ASCII code for first character of String (example for ‘E’)

19 - 62

0xFF

Rest of lower half of EEPROM is available for longer strings, up

to 50 characters maximum (set unused locations to 0xFF)

64-126

0xFF

Leave upper half of EEPROM empty

(may be used to hold special setup information - contact

STMicroelectronics for details)

127

0xAA

Special flag to indicate that EEPROM is present