Signal Descriptions
5-57
18524C/0—Nov1996
AMD-K5 Processor Technical Reference Manual
5.2.19
DP7–DP0 (Data Parity)
Bidirectional
Summary
DP7–DP0 carry the even-parity bits for each byte driven and
sampled on the D63–D0 data bus. While DP7–DP0 are outputs,
system logic can use the signals to check parity. While DP7–
DP0 are inputs, the processor uses them to determine the state
of the PCHK output.
Driven, Sampled, and
Floated
DP7–DP0 are driven, sampled, and floated with the same tim-
ing as D63–D0. See the description for D63–D0 on page 5-55.
Details
DP7 corresponds to the high byte on the data bus (D63–D56)
and DP0 corresponds to the low byte on the data bus (D7–D0).
To determine data parity, the bit values driven for each byte
on DP7–DP0 are considered with the bit values driven for each
byte on D63–D0. For example, if the total number of 1 bits for
the byte on D63–D56 is even for DP7 and D63–D56, the address
is considered free of error (thus the term even parity). If the
number of 1 bits is odd, the byte is considered to have an error.
During single-transfer read cycles, parity is only checked for
enabled bytes as specified by BE7–BE0. During burst reads,
parity is checked for all eight bytes, regardless of BE7–BE0. If
a parity error is detected on a read, the processor asserts
PCHK.
Systems that do not implement data parity generation and
checking should tie DP7–DP0 either High or Low and ignore
the PCHK output. In addition to generating and checking data
parity, the processor also generates and checks address parity
using the AP and APCHK signals. See page 5-31 and 5-32 for
details.
Summary of Contents for AMD-K5
Page 1: ...AMD K5 Processor Technical Reference Manual TM...
Page 10: ...x AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 24: ...1 4 Overview AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 54: ...2 30 Internal Architecture AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 116: ...4 26 Performance AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 356: ...6 44 System Design AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 380: ...7 24 Test and Debug AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 396: ...A 16 AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 406: ...I 10 Index AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...