
136
Signal Descriptions
Chapter 5
AMD-K6-2E+ Embedded Processor Data Sheet
23542A/0—September 2000
Preliminary Information
5.52
VCC2H/L# (VCC2 High/Low)
Pin Attribute
Output (supported on the CPGA package only)
Summary
VCC2H/L# is internally tied to V
SS
(logic level 0) to indicate to
the system logic that it must supply the specified processor core
voltage to the V
CC2
pins. The V
CC2
pins supply voltage to the
processor core, independent of the voltage supplied to the I/O
buffers on the V
CC3
pins. Upon sampling VCC2DET Low to
identify dual-voltage processor requirements, system logic
should sample VCC2H/L# to identify the core voltage
requirements: 2.9-V and 3.2-V products (High) or 2.4-V and
lower products (Low).
I
VCC2H/L# is only driven High on older legacy (0.35-micron
process technology) AMD-K6 processors to indicate core
voltages of 2.9 V and 3.2 V.
VCC2H/L# is driven Low for all AMD-K6 processors with a
core voltage requirement of 2.4 V or less. Note that all AMD
products based on the 0.18-micron process technology,
including the AMD-K6-2E+ processor, are 2.0 V or less.
I
Note that this pin is not supported on the OBGA package.
Driven
VCC2H/L# always equals 0 and is never floated for 2.4-V and
lower products
—even during the Three-State Test mode. To
ensure proper operation for 2.9-V and 3.2-V products, system
logic that samples VCC2H/L# should design a weak pullup
resistor for this signal.
Table 18. Output Pin Float Conditions for VCC2 High/Low
Name
VCC2DET
1
VCC2H/L#
1
Floated At:
Notes:
1.
All outputs except VCC2DET, VCC2H/L#, and TDO float during the Three-State Test mode.
Always Driven
Always Driven