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20

Agere Systems Inc.

Data Sheet, Rev. 3

May 2004

Two-Cable Transceiver/Arbiter Device

FW802B Low-Power PHY IEEE 1394A-2000

Internal Register Configuration

The PHY register map is shown below in Table 8. (Refer to IEEE 1394a-2000, 5B.1 for more information).

Table 8. PHY Register Map for the Cable Environment

The meaning of the register fields within the PHY register map are defined by Table 9 below. Power reset values

not specified are resolved by the operation of the PHY state machines subsequent to a power reset.

Table 9. PHY Register Fields for the Cable Environment

Address

Contents

Bit 0

Bit 1

Bit 2

Bit 3

Bit 4

Bit 5

Bit 6

Bit 7

Physical_ID

R

PS

RHB

IBR

Gap_count

Extended (7)

XXXXX

Total_ports

Max_speed

XXXXX

Delay

LCtrl

Contender

Jitter

Pwr_class

Watchdog

ISBR

Loop

Pwr_fail

Timeout

Port_event Enab_accel Enab_multi

XXXXX XXXXX XXXXX XXXXX XXXXX XXXXX XXXXX

XXXXX

Page_select

XXXXX

Port_select

REQUIRED

Field

Size Type

Power Reset

Value

Description

Physical_ID

6

r

000000

The address of this node determined during self-identification. A

value of 63 indicates a malconfigured bus; the link will not transmit

any packets.

R

1

r

0

When set to one, indicates that this node is the root.

PS

1

r

—

Cable power active.

RHB

1

rw

0

Root Hold-off Bit. When set to one, the force_root variable is

TRUE, which instructs the PHY to attempt to become the root dur-

ing the next tree identify process.

IBR

1

rw

0

Initiate Bus Reset. When set to one, instructs the PHY to set ibr

TRUE and reset_time to RESET_TIME. These values in turn

cause the PHY to initiate a bus reset without arbitration; the reset

signal is asserted for 166

µs. This bit is self-clearing.

Gap_count

6

rw

Used to configure the arbitration timer setting in order to optimize

gap times according to the topology of the bus. See Section 4.3.6

of IEEE Standard 1394a-2000 for the encoding of this field.

Extended

3

r

7

This field has a constant value of seven, which indicates the

extended PHY register map.