
3-10
Signal Descriptions
3.3.2 Address and Data Signals
Table 3.7
describes the Address and Data Signals group.
Table 3.7
Address and Data Signals
Name
Bump
Type Strength Description
AD[63:0]
Y5, AB5, AC5, AA6,
Y6, AB6, AC6, AA7,
AB7, AC7, AA8, Y8,
AB8, AC8, AA9, Y9,
AB9, AC9, AA10,
Y11, AB10, AC10,
AA11, AC11, AB11,
AC12, AA12, AB12,
AB13, AC13, AA13,
AC14, H1, J3, J4, J2,
J1, K3, L4, K2, L1,
L2, M1, M3, M2, N2,
N1, N3, T4, T3, U1–
U3, V1, V2, V4, W1,
W2, W4, W3, Y1, Y2,
AA1, Y3.
T/S
8 mA
PCI
Physical longword
Address and Data
are
multiplexed on the same PCI pins. A bus
transaction consists of an address phase
followed by one or more data phases. During
the first clock of a transaction, AD[63:0]
contain a 64-bit physical byte address. If the
command is a dual address cycle (DAC),
implying a 64-bit address, AD[31:0] will contain
the upper 32 bits of the address during the
second clock of the transaction. During
subsequent clocks, AD[63:0] will contain data.
PCI supports both read and write bursts.
AD[7:0] define the least significant byte, and
AD[63:56] define the most significant byte.
C_BE[7:0]/
AA4, AC3, AB4,
AC4, K1, P1, T2, V3.
T/S
8 mA
PCI
Bus
Command and Byte Enables
are
multiplexed on the same PCI pins. During the
address phase of a transaction, C_BE[3:0]/
define the bus command. If the transaction is
a DAC, C_BE[3:0]/ contain the DAC command
and C_BE[7:4]/ define the bus command.
C_BE[3:0]/ define the bus command during the
second clock of the transaction. During the
data phase, C_BE[7:0]/ are used as byte
enables. The byte enables determine which
byte lanes carry meaningful data: C_BE[0]/
applies to byte 0, and C_BE[7]/ to byte 7.
PAR
T1
T/S
8 mA
PCI
Parity
is the even parity bit that protects the
AD[31:0] and C_BE[3:0]/ lines. During the
address phase, both the address and
command bits are covered. During the data
phase, both the data and byte enables are
covered.