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About a timing between Data Valid and DTACK Active in DTACK mode Read Access for i.MX6

Question asked by yuuki on Jan 14, 2016
Latest reply on Jan 31, 2016 by Yuri Muhin

Dear all,

 

We want to use DTACK mode of EIM.

We referred to the following part of the data sheet.

 

IMX6DLIEC.pdf (Rev.5)

- Figure 21. DTACK Mode Read Access (DAP=0)

- Table 38. EIM Asynchronous Timing Parameters Table Relative Chip to Select

 

We have the following question about a timing for DTACK mode Read Access.

 

I understand that the DTACK signal should become active after the Data valid.

Is my understanding right?

 

 

According to Figure 21,

the DTACK signal becomes active after the Data valid.

 

However, according to Table 38,

"Input Data Valid to EIM_CSx_B Invalid"(WE43) is Min "MAXCO - MAXCSO + MAXDI"ns.

   => MAXCO(10ns) - MAXCSO(10) + MAXDI(5ns) = 5ns

 

"EIM_DTACK_B Active to EIM_CSx_B Invalid"(WE47) is Min "MAXCO - MAXCSO + MAXDTI"ns.

   => MAXCO(10ns) - MAXCSO(10) + MAXDTI(10ns) = 10ns

 

For the timing, the Data becomes valid after DTACK active.

 

How should I understand the explanation of the data sheet?

 

 

May I have advice?

 

Best Regards,

Yuuki

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