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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 VSS (logic level 0) to indicate to
the system logic that it must supply the specified processor core
voltage to the VCC2 pins. The VCC2 pins supply voltage to the
processor core, independent of the voltage supplied to the I/O
buffers on the VCC3 pins. Upon sampling VCC2DET Low to
identify dual-voltage processor requirements, system logic
sh ould sa mp le VCC 2 H/L# to id entif y the core vo l tage
requirements: 2.9-V and 3.2-V products (High) or 2.4-V and
lower products (Low).
s
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.
s
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.
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
Floated At:
VCC2DET1
Notes:
1. All outputs except VCC2DET, VCC2H/L#, and TDO float during the Three-State Test mode.
Always Driven
Always Driven