AM79C972BVCW datasheet(95/130 Pages) AMD

95 / 130 page

Am79C972

USER ACCESSIBLE REGISTERS

The Am79C972 controller has three types of user reg-

isters: the PCI configuration registers, the Control and

Status registers (CSR), and the Bus Control registers

(BCR).

The Am79C972 controller implements all PCnet-ISA

(Am79C960) registers, all C-LANCE (Am79C90) regis-

ters, plus a number of additional registers. The

Am79C972 CSRs are compatible upon power up with

both the PCnet-ISA CSRs and all of the C-LANCE

CSRs.

The PCI configuration registers can be accessed in any

data width. All other registers must be accessed ac-

cording to the I/O mode that is currently selected.

When WIO mode is selected, all other register loca-

tions are defined to be 16 bits in width. When DWIO

mode is selected, all these register locations are de-

fined to be 32 bits in width, with the upper 16 bits of

most register locations marked as reserved locations

with undefined values. When performing register write

operations in DWIO mode, the upper 16 bits should al-

ways be written as zeros. When performing register

read operations in DWIO mode, the upper 16 bits of

I/O resources should always be regarded as having un-

defined values, except for CSR88.

The Am79C972 registers can be divided into four

groups: PCI Configuration, Setup, Running, and Test.

Registers not included in any of these categories can

be assumed to be intended for diagnostic purposes.

n PCI Configuration Registers

These registers are intended to be initialized by the

system initialization procedure (e.g., BIOS device ini-

tialization routine) to program the operation of the

Am79C972 controller PCI bus interface.

The following is a list of the registers that would typi-

cally need to be programmed once during the initializa-

tion of the Am79C972 controller within a system:

— PCI I/O Base Address or Memory Mapped I/O

Base Address register

— PCI Expansion ROM Base Address register

— PCI Interrupt Line register

— PCI Latency Timer register

— PCI Status register

— PCI Command register

— OnNow register

n Setup Registers

These registers are intended to be initialized by the de-

vice driver to program the operation of various

Am79C972 controller features.

The following is a list of the registers that would typi-

cally need to be programmed once during the setup of

the Am79C972 controller within a system. The control

bits in each of these registers typically do not need to

be modified once they have been written. However,

there are no restrictions as to how many times these

registers may actually be accessed. Note that if the de-

fault power up values of any of these registers is ac-

ceptable to the application, then such registers need

never be accessed at all.

Note: Registers marked with “^” may be programma-

ble through the EEPROM read operation and, there-

fore, do not necessarily need to be written to by the

system initialization procedure or by the driver soft-

ware. Registers marked with “*” will be initialized by the

initialization block read operation.

CSR1

Initialization Block Address[15:0]

CSR2*

Initialization Block Address[31:16]

CSR3

Interrupt Masks and Deferral Control

CSR4

Test and Features Control

CSR5

Extended Control and Interrupt

CSR7

Extended Control and Interrupt2

CSR8*

Logical Address Filter[15:0]

CSR9*

Logical Address Filter[31:16]

CSR10*

Logical Address Filter[47:32]

CSR11*

Logical Address Filter[63:48]

CSR12*^

Physical Address[15:0]

CSR13*^

Physical Address[31:16]

CSR14*^

Physical Address[47:32]

CSR15*

Mode

CSR24*

Base Address of Receive Ring Lower

CSR25*

Base Address of Receive Ring Upper

CSR30*

Base Address of Transmit Ring Lower

CSR31*

Base Address of Transmit Ring Upper

CSR47*

Transmit Polling Interval

CSR49*

Receive Polling Interval

CSR76*

Receive Ring Length

CSR78*

Transmit Ring Length

CSR80

DMA Transfer Counter and FIFO Thresh-

old Control

CSR82

Bus Activity Timer

CSR100

Memory Error Timeout

CSR116^

OnNow Miscellaneous

CSR122

Receiver Packet Alignment Control

AM79C972BVCW Datasheet(PDF) 95 Page - Advanced Micro Devices

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