PCI9060ES datasheet(22/192 Pages) ETC

22 / 192 page

SECTION 3

PCI 9080

FUNCTIONAL DESCRIPTION

©PLX Technology, Inc., 1997

Page 13

Version 1.02

Table 3-1. NB# and Serial EEPROM Guidelines

NB#

Serial

EEPROM

System Boot Condition

Boot with PCI 9080 default values.

Programmed

Boot with serial EEPROM values.

Low

Blank

Not recommended (uses default

values).

Local processor programs PCI 9080

registers, then sets Local Init Status

(Table 4-59[31] = done).

Note:

Some systems hang if Direct

Slave reads and writes take too long

(during initialization, the PCI host also

performs Direct Slave accesses). Value

of PCI Target Retry Delay Clocks

(Table 4-39[31:28]) may resolve this

problem.

Programmed

Load serial EEPROM, but local

processor can reprogram PCI 9080.

High

Blank

Load serial EEPROM (default values),

but local processor can reprogram PCI

9080. System can boot.

Note:

Serial EEPROM can be

programmed through PCI 9080 after

system boots in this condition.

3.2.1 Serial EEPROM Initialization

During serial EEPROM initialization, PCI 9080 response

to PCI target accesses is RETRY. During serial

EEPROM initialization, PCI 9080 response to a local

processor is to hold off READYo#.

3.2.2 Local Initialization

PCI 9080 issues a RETRY to all PCI accesses until the

"Local Init Done bit" in the Init Control Register is set.

"Init Done bit" is programmable through local bus

configuration accesses. If this bit is not going to be set

by a local processor, then NB# input should be tied low.

Holding NB# input low externally forces the Local Init

Done bit to 1.

PCI 9080 default values are used if a serial EEPROM is

not present and local Init Status bit is set to 1 by holding

the NB# input low or set by the local processor.

3.3 SERIAL EEPROM

After reset, PCI 9080 attempts to read the serial

EEPROM to determine its presence. An active low start

bit indicates the serial EEPROM is present (PCI 9080

supports 93CS46 (1K) or 93CS56 (2K), selectable by

way of the EESEL pin). (Refer to the manufacturer’s

data sheet for the particular serial EEPROM being

used.) The first word is then checked to verify the serial

EEPROM is programmed. If the first word (16 bit) is all

ones, a blank serial EEPROM PCI 9080 uses default

values instead.

The 5 V serial EEPROM clock (EESK, pin 173) is

derived from the PCI clock. PCI 9080 generates the

serial EEPROM clock by internally dividing the PCI clock

by 32.

The serial EEPROM can be read or programmed from

the PCI or local bus. Bits [27:24] of the Serial EEPROM

Control Register (refer to Table 4-59[27:24]) controls the

PCI 9080 pins that enable the reading or writing of serial

EEPROM data bits. (Refer to the manufacturer’s data

sheet for the particular serial EEPROM being used.)

PCI 9080 has three serial EEPROM load options:

•

Short Load Mode—SHORT# input pin is pulled

down and PCI 9080 loads five Lwords from the

serial EEPROM

•

Long Load Mode—SHORT# input pin is pulled up,

bit 25 of the Local Bus Region Descriptor Register

(LOC:98h) is set to 0, and PCI 9080 loads

17 Lwords from the serial EEPROM (refer to Table

4-39)

•

Extra Long Load Mode—SHORT# input pin is

pulled up, bit 25 of the Local Bus Region Descriptor

from the serial EEPROM, and PCI 9080 loads

21 Lwords from the serial EEPROM (refer to Table

4-39)

3.3.1 Short Serial EEPROM Load

The registers listed in Table 3-2 are loaded from serial

EEPROM after reset is de-asserted if SHORT# pin is

low. The serial EEPROM is organized in words (16 bit).

PCI 9080 first loads MSW (Most Significant Word; bits

[31:16]), starting from the most significant bit (bit 31).

PCI 9080 then loads LSW (Least Significant Word; bits

[15:0]), starting again from the most significant bit (bit

15). Therefore, PCI 9080 loads Device ID, Vendor ID,

class code, and so forth. The five 32-bit words are stored

sequentially in the serial EEPROM.

PCI9060ES Datasheet(PDF) 22 Page - List of Unclassifed Manufacturers

PCI9060ES Datasheet(HTML) 22 Page - List of Unclassifed Manufacturers

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL