4 pci bus commands, Figure 10-3 – Freescale Semiconductor MPC5200B User Manual

Page 344

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Functional Description

MPC5200B Users Guide, Rev. 1

Freescale Semiconductor

10-47

Figure 10-3. PCI Write Terminated by Target

10.4.1.4

PCI Bus Commands

PCI supports a number of different commands. These commands are presented by the initiator on the C/BE[3:0] lines during the address phase
of a PCI transaction.

Table 10-5. PCI Bus Commands

C/BE[3:0]

PCI Bus

Command

MPC5200B

supports as

Initiator

MPC5200B

supports

as Target

Definition

0000

Interrupt

Acknowledge

Yes

No

The interrupt acknowledge command is a read
(implicitly addressing an external interrupt
controller). Only one device on the PCI bus should
respond to the interrupt acknowledge command.

0001

Special Cycle

Yes

No

The Special Cycle command provides a
mechanism to broadcast select messages to all
devices on the PCI bus.

0010

I/O-read

Yes

No

The I/O-read command accesses agents mapped
into the PCI I/O space.

0011

I/O-write

Yes

No

The I/O-write command accesses agents mapped
into the PCI I/O space.

0100

Reserved

No

No

--

0101

Reserved

No

No

--

0110

Memory-read

Yes

Yes

The memory read command accesses agents
mapped into PCI memory space.

A1

D1

D2

1

2

3

4

5

6

7

8

CMD

Byte Enables

Address

Phase

Data Phase 1

Data Phase 2

STOP

CLK

FRAME

C/BE

IRDY

TRDY

DEVSEL

AD

(wait)

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