TI380PCIA Datasheet, PDF (15/40 Pages) Texas Instruments – PCI BUS INTERFACE FOR THE TI380 COMMPROCESSORS

TI380PCIA
PCI BUS INTERFACE FOR THE TI380 COMMPROCESSORS™
SPWS035 – JUNE 1997
serial EEPROM interface (EIF) (continued)
Several copies of the BIA can be programmed into the EEPROM user-defined space as a protection against
inadvertent modification of the copy of the BIA at addresses 0x09 – 0x0E.
In systems that do not use an EEPROM, the EDC pin should be tied low and the EDIO pin should be tied high.
This action causes default values to be loaded into the configuration registers as shown in Table 2. EDC and
EDIO are sampled at the deassertion of RST. If EDC is low and EDIO is high at the deassertion of reset, the
TI380PCIA functions as if no EEPROM is present in the system.
PARAMETER DESCRIPTION
Vendor ID least significant byte
Vendor ID most significant byte
Device ID least significant byte
Device ID most significant byte
Revision ID
Sub-class
Min_Gnt
Max_Lat
Checksum
Burned-in address
TI2000 reserved byte
Reserved for future use
User-defined
Table 2. EIF Configuration Registers
EEPROM BYTE ADDRESS
0x00
0x01
0x02
0x03
0x04
0x05
0x06
0x07
0x08
0x09
0x0A
0x0B
0x0C
0x0D
0x0E
0x0F
0x10
0x11
0x12 ... 0x20
0x21 ... 0xFF
DEFAULT VALUE
0x4C
0x10
0x08
0x05
0x01
0x80
0x01
0x00
0x7A
BIA MSbyte
BIA byte
BIA byte
BIA byte
BIA byte
BIA LSbyte
BIA most significant checksum
BIA least significant checksum
0x01
Reserved
User-defined
The default values for the parameters stored in the EEPROM can always be accessed by software because
copies of these values are stored in a series of hardwired registers in the TI380PCIA configuration space (see
Table 3). These registers are read-only and are unaffected by the process of loading data from the optional
EEPROM.
Table 3. Hardwired Registers in TI380PCIA Configuration Space
PARAMETER DESCRIPTION
Vendor ID
Device ID
Revision ID
Subclass
Min_Gnt
Max_Lat
HARDWIRED REGISTER NAME
(CONTAINS READ-ONLY COPY
OF DEFAULT VALUE)
Hardwired vendor ID
Hardwired device ID
Hardwired revision ID
Hardwired subclass
Hardwired Min_Gnt
Hardwired Max_Lat
REGISTER ADDRESS IN TI380PCIA
CONFIGURATION SPACE
4C
4C
50
50
50
50
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