Datasheet

1394 OHCI Memory-Mapped Register Space
130
March 5 2007 − June 2011SCPS154C
8.2 GUID ROM Register
The GUID ROM register accesses the serial EEPROM, and is only applicable if bit 24 (GUID_ROM) in the
OHCI version register at OHCI offset 00h (see Section 8.1) is set to 1b. See Table 8−3 for a complete
description of the register contents.
OHCI register offset: 04h
Register type: Read/Set/Update, Read/Update, Read-only
Default value: 00XX 0000h
BIT NUMBER 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
RESET STATE 0 0 0 0 0 0 0 0 X X X X X X X X
BIT NUMBER 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
RESET STATE 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Table 8−3. GUID ROM Register Description
BIT FIELD NAME TYPE DESCRIPTION
31 addrReset RSU Software sets bit 31 to 1b to reset the GUID ROM address to 0. When the controller completes the reset,
it clears this bit. The controller does not automatically fill bits 23−16 (rdData field) with the 0
th
byte.
30−26 RSVD R Reserved. Bits 30−26 return 00 0000b when read.
25 rdStart RSU A read of the currently addressed byte is started when bit 25 is set to 1b. This bit is automatically cleared
when the controller completes the read of the currently addressed GUID ROM byte.
24 RSVD R Reserved. Bit 24 returns 0b when read.
23−16 rdData RU This field contains the data read from the GUID ROM.
15−8 RSVD R Reserved. Bits 15−8 return 00h when read.
7−0 miniROM R The miniROM field defaults to 00h indicating that no mini-ROM is implemented. If an EEPROM is
implemented, then all 8 bits of this miniROM field are downloaded from EEPROM word offset 28h. For
this device, the miniROM field must be greater than 39h to indicate a valid miniROM offset into the
EEPROM.
Not Recommended for New Designs