AMD ATHLON 8 - CONNECT Pin; COREFB and COREFB# Pins; CPU_PRESENCE# Pin; DBRDY and DBREQ# Pins

Chapter 11 Pin Descriptions 75
25175H—March 2003 AMD Athlon™ XP Processor Model 8 Data Sheet
Preliminary Information
CONNECT Pin CONNECT is an input from the system used for power
management and clock-forward initialization at reset.
COREFB and
COREFB# Pins
COREFB and COREFB# are outputs to the system that provide
processor core voltage feedback to the system.
CPU_PRESENCE# Pin CPU_PRESENCE# is connected to VSS on the processor
package. If pulled-up on the motherboard, CPU_PRESENCE#
may be used to detect the presence or absence of a processor in
the Socket A-style socket.
DBRDY and DBREQ#
Pins
DBRDY and DBREQ# are routed to the debug connector.
DBREQ# is tied to V
CC_CORE
with a pullup resistor.
FERR Pin FERR is an output to the system that is asserted for any
unmasked numerical exception independent of the NE bit in
CR0. FERR is a push-pull active High signal that must be
inverted and level shifted to an active Low signal. For more
information about FERR and FERR#, see the “Required
Circuits” chapter of the AMD Athlon™ Processor-Based
Motherboard Design Guide, order# 24363.
FID[3:0] Pins FID[3] (Y3), FID[2] (Y1), FID[1] (W3), and FID[0] (W1) are the
4-bit processor clock-to-SYSCLK ratio.
Table 26 on page 76 shows the encodings of the clock
multipliers on FID[3:0].