Psion Teklogix OMNii HDK XT10, Руководство пользователя

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Chapter 8: EEPROM Specifications
EEPROM Reading/Writing
Psion Teklogix Omnii HDK User Manual 119
• Hardware Revision – This field will be displayed to the user in the System Properties panel
of the System applet in the Control Panel. This field is optional, but if used it will be at this
known location and contain printable ASCII text. If the ASCII string is less than 4 bytes, it
must be null-terminated.
• EEPROM Size – This byte identifies the EEPROM size. This size may be programmed
to be smaller than the actual capacity of the part installed. If it is not programmed (ie 0xFF),
the size will default to 128 bytes. Software will not be able to access any data beyond this
configured size.
• Reserved – The bytes in this field are reserved for future use and must be defaulted to or
programmed as 0xFF.
• Module Specific Parameters – Starting at this address parameters specific to the module
type can be appended.
8.4 EEPROM Reading/Writing
EEPROMs on devices attached to Omnii are read using the Hdk7545_ReadEepromHeader
function (see Section 4.7.4.18 on page 52), and modified using the
Hdk7545_WriteEepromHeader function (see Section 4.7.4.19 on page 53). These functions use
the Hdk7545_Eeprom structure (see page 57) to perform reads and writes.
The HDK Demo application program included with the Omnii HDK can be used to more easily
read and write these fields. See Chapter 10: “HDK Demo Application” for information on how to
install and use this application, and Section 10.6.2.4: “EEPROM” for specific details regarding
EEPROM reading and writing.
Warning: Setting a field size larger than the actual EEPROM size is likely to result in
unexpected behaviour.
Note: For more information on the C functions, structures and constants that appear in this
section, refer to Section 4.7: “Omnii HDK Application Development Software”.