AMD SC1201, SC1200 manual Power Planes of External Interface Signals, DC Current

Electrical Specifications 32579B

Table 9-4indicates which power rails are used for each signal of the SC1200/SC1201 processor’s external interface. Power planes not listed in this table are internal, and are not related to signals of the external interface.

Table 9-4. Power Planes of External Interface Signals

Power Plane	Signal Names	VCC Balls	VSS Balls
Standby	GPWIO[0:2], LED#, ONCTL#, PWRBTN#, PWRCNT[1:2],	VSB	VSS
	THRM#, CLK32, IRRX1, RI2#, SDATA_IN2
Battery	X32I, X32O	VBAT	VSS
CRT DAC	RED, GREEN, BLUE, VREF, SETRES	AVCCCRT	AVSSCRT
TV DAC	CVBS, SVY, SVC, TVB, TVR, Cr, Cab, Y, TVREF, TVRSET,	AVCCTV	AVSSTV
	TVIOM, TVCOMP
USB	DPOS_PORT1, DNEG_PORT1, DPOS_PORT2,	AVCCUSB	AVSSUSB
	DNEG_PORT2, DPOS_PORT3, DNEG_PORT3
I/O	All other external interface signals	VIO	VSS

9.1.5DC Current

DC current is not a simple measurement. Three of the SC1200/SC1201 processor’s power states (On, Active Idle, Sleep) were selected for measurement. For each power state measured, two functional characteristics (Typical Average, Absolute Maximum) are used to determine how much current the SC1200/SC1201 processor uses.

9.1.5.1Power State Parameter Definitions

The DC characteristics tables in this section list Core and I/O current for three of the power states. For more explana- tion on the SC1200/SC1201 processor’s power states see Section 6.2.9 "Power Management Logic" on page 158.

•On (C0): All internal and external clocks with respect to the SC1200/SC1201 processor are running and all func- tional blocks inside the GX1 module (CPU Core, Memory Controller, Display Controller, etc.) are actively generating cycles. This is equivalent to the ACPI specifi- cation’s “S0,C0” state.

•Active Idle (C1): The CPU Core has been halted, all other functional blocks (including the Display Controller for refreshing the display) are actively generating cycles. This state is entered when a HLT instruction is executed by the CPU Core. From a user’s perspective, this state is indistinguishable from the On state and is equivalent to the ACPI specification’s “S0,C1” state.

•Sleep (SL2): This is the lowest power state the SC1200/SC1201 processor can be in with voltage still applied to the device’s core and I/O supply pins. This is equivalent to the ACPI specification’s “S1” state.

9.1.5.2Definition and Measurement Techniques of Current Parameters

These parameters describe the current while the SC1200/SC1201 processor is in the On state:

•Typical Average: Indicates the average current used by the SC1200/SC1201 processor while in the On state. This is measured by running typical Windows applica- tions in a typical display mode. In this case, 800x600x8 bpp at 75 Hz, 50 MHz DCLK using a background image of vertical stripes (4-pixel wide) alternating between black and white with power management disabled (to guarantee that the SC1200/SC1201 processor never goes into the Active Idle state). This number is provided for reference only since it can vary greatly depending on the usage model of the system.

Note: This typical average should not be confused with the typical power numbers. Typical power is based on a combination of On (Typical Average) and Active Idle states.

•Absolute Maximum: Indicates the maximum instanta- neous current used by the SC1200/SC1201 processor. CPU Core current is measured by running the Landmark Speed 200 benchmark test (with power management disabled) and measuring the peak current at any given instant during the test. I/O current is measured by running Microsoft Windows 98 and using a background image of vertical stripes (1-pixel wide) alternating between black and white at the maximum display resolu- tion of each of the display type supported (CRT, TFT, and TV).

AMD Geode™ SC1200/SC1201 Processor Data Book 367