AMD SC1200, SC1201 manual Memory Interface Signals, Column Address Strobe. RAS#, CAS#, WE# and CKE

32579B Signal Definitions

3.4.1System Interface (Continued)

Signal Name	Ball No.	Type	Description	Mux
X32I	AJ2	I/O	Crystal Connections. Connected directly to a 32.768	---
			KHz crystal. This clock input is required even if the inter-
X32O	AJ3			---
			nal RTC is not being used. Some of the internal clocks
			are derived from this clock. If an external clock is used, it
			should be connected to X32I, using a voltage level of 0
			volts to VCORE +10% maximum. X32O should remain
			unconnected.
X27I	AG3	I/O	Crystal Connections. Connected directly to a	---
			27.000 MHz crystal. This clock input is used for video cir-
X27O	AH2			---
			cuits. Some of the internal clocks are derived from this
			clock. If the internal TV encoder is used, a 25 ppm crystal
			is recommended. If an external clock is used, it should be
			connected to X27I, using a voltage level of 0 volts to VIO
			and X27O should be remain unconnected.
CLK27M	AA4	O	27 MHz Output Clock. Output of crystal oscillator.	IDE_DATA5
PCIRST#	A6	O	PCI and System Reset. PCIRST# is the reset signal for	---
			the PCI bus and system. It is asserted for approximately
			100 µs after POR# is negated.

3.4.2Memory Interface Signals

Signal Name	Ball No.	Type	Description	Mux
MD[63:0]	See	I/O	Memory Data Bus. The data bus lines driven to/from	---
	Table 3-3		system memory.
	on page
	40
MA[12:0]	See	O	Memory Address Bus. The multiplexed row/column	---
	Table 3-3		address lines driven to the system memory. Supports
	on page		256-Mbit SDRAM.
	40
BA1	AK14	O	Bank Address Bits. These bits are used to select the	---
			component bank within the SDRAM.
BA0	AJ13			---
CS1#	AH27	O	Chip Selects. These bits are used to select the module	---
			bank within system memory. Each chip select corre-
CS0#	AL12			---
			sponds to a specific module bank. If CS# is high, the
			bank(s) do not respond to RAS#, CAS#, and WE# until
			the bank is selected again.
RASA#	AK12	O	Row Address Strobe. RAS#, CAS#, WE# and CKE are	---
			encoded to support the different SDRAM commands.
			RASA# is used with CS[1:0]#.
CASA#	AJ12	O	Column Address Strobe. RAS#, CAS#, WE# and CKE	---
			are encoded to support the different SDRAM commands.
			CASA# is used with CS[1:0]#.
WEA#	AH12	O	Write Enable. RAS#, CAS#, WE# and CKE are encoded	---
			to support the different SDRAM commands. WEA# is
			used with CS[1:0]#.

50 AMD Geode™ SC1200/SC1201 Processor Data Book