Texas Instruments specifications Sdram interface TNETX3270 Terminal Interface to SDRAMs

TNETX3270

ThunderSWITCH 24/3 ETHERNET SWITCH

WITH 24 10-MBIT/S PORTS AND 3 10-/100-MBIT/S PORTS

SPWS043B ± NOVEMBER 1997 ± REVISED APRIL 1999

SDRAM interface (continued)

Table 15. TNETX3270 Terminal Interface to SDRAMs

TERMINALS		SDRAM TERMINAL FUNCTION
TNETX3270	SDRAM
DA13	A13	Row/bank address (64-M SDRAMs only)
DA12	A12	Row/bank address (64-M SDRAMs only)
DA11	A11	Row/bank address
DA10	A10	Row address/auto-precharge select
DA09	A9	Row address
DA08	A8	Row address/column address (⋅ 8 only)
DA07	A7	Row address/column address
DA06	A6	Row address/column address
DA05	A5	Row address/column address
DA04	A4	Row address/column address
DA03	A3	Row address/column address
DA02	A2	Row address/column address
DA01	A1	Row address/column address
DA00	A0	Row address/column address
DRAS	RAS	Row address strobe
DCAS	CAS	Column address strobe
DW	W	Write enable
DCLK	CLK	Clock
DD31±DD16	DQ15±DQ0	SDRAM1. Data I/O (⋅ 16 SDRAMs)
DD15±DD00	DQ15±DQ0	SDRAM0
DD31±DD24	DQ7±DQ0	SDRAM3. Data I/O (⋅ 8 SDRAMs)
DD23±DD16	DQ7±DQ0	SDRAM2
DD15±DD08	DQ7±DQ0	SDRAM1
DD07±DD00	DQ7±DQ0	SDRAM0

DA13 and DA12 should be left unconnected if 16M-bit SDRAMs are used. The remaining functional SDRAM terminals that are not directly controlled by the SDRAM interface should be tied off from the external system during operation (see Table 16).

Table 16. SDRAM Terminals Not Driven by the TNETX3270

HELD	SDRAM	SDRAM
	TERMINAL	TERMINAL FUNCTION
Low	CS	Chip select
High	CKE	CLK enable
Low	DQM	Data mask (⋅ 8 SDRAMs)
Low	DQML	Data mask (⋅ 16 SDRAMs)
Low	DQMU	Data mask (⋅ 16 SDRAMs)

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