Texas Instruments TMS320DM646X DMSOC manual Example Using TC5516100FT-12

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3.1.4Example Using TC5516100FT-12

This section takes you through the configuration steps required to implement Toshiba’s TC55V1664FT-12 ASRAM with the EMIF. The following assumptions are made:

•ASRAM is connected to chip select space 3 (EM_CS[3])

•EMIF clock speed is 100 MHZ (tcyc = 10 nS)

Table 20 lists the data sheet specifications for the EMIF and Table 21 lists the data sheet specifications for the ASRAM.

Table 20. EMIF Timing Requirements for TC5516100FT-12 Example

Parameter	Description					Min	Max	Units
tSU	Data Setup time, data valid before				high	5		nS
			EM_OE
tH	Data Hold time, data valid after			high		0		nS
		EM_OE

Table 21. ASRAM Timing Requirements for TC5516100FT-12 Example

Parameter	Description	Min	Max	Units
tACC	Address Access time		12	nS
tOH	Output data Hold time for address change	3		nS
tRC	Read cycle time	12		nS
tWP	Write Pulse width	8		nS
tAW	Address valid to end of Write	9		nS
tDS	Data Setup time	7		nS
tWR	Write Recovery time	0		nS
tDH	Data Hold time	0		nS
tWC	Write Cycle time	12		nS
tCOD	Output Disable time from chip enable		7

Table 22 lists the values of the PCB board delays. The delays were estimated using the rule that there is 180 pS of delay for every 1 inch of trace.

Table 22. Measured PCB Delays for TC5516100FT-12 Example

Parameter Description Delay (ns)

Read Access

tEM_CS

tEM_A

tEM_OE

tEM_D

Delay on EM_CS from EMIF to ASRAM. EM_CS is driven by EMIF.					0.36
Delay on EM_A from EMIF to ASRAM. EM_A is driven by EMIF.					0.27
Delay on		from EMIF to ASRAM.		is driven by EMIF.	0.36
	EM_OE		EM_OE
Delay on EM_D from ASRAM to EMIF. EM_D is driven by ASRAM.					0.45

Write Access

tEM_CS

tEM_A

tEM_WE

tEM_D

Delay on EM_CS from EMIF to ASRAM. EM_CS is driven by EMIF.					0.36
Delay on EM_A from EMIF to ASRAM. EM_A is driven by EMIF.					0.27
Delay on		from EMIF to ASRAM.		is driven by EMIF.	0.36
	EM_WE		EM_WE
Delay on EM_D from EMIF to ASRAM. EM_D is driven by EMIF.					0.45

SPRUEQ7C –February 2010	Asynchronous External Memory Interface (EMIF)	37
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