Max EMIF clock???

Alexander Khvilivitzky

Please help determine max EMIF clock - documentation is ambiguous and lacks detail.

From SPRS457D, fig.3-2 - looks like AEMIF source clock is PLLC1SYSCLK4. Its max value from SPRS457D, table 3-4 is 135 MHz.

However, in SPRUFG5A, p.171 - AEMIF clock is referenced as PLLC1SYSCLK4/2. Which is exactly what I see when trying to access a NOR flash. If this is true, the maximum AEMIF clock is 67.5 MHz.

SPRUFI1 on the other hand has examples mentioning 100MHz EMIF clock. (Pp.43, 51).

Am I missing something?

over 14 years ago

0 Tai Nguyen over 14 years ago

TI__Expert 5955 points

Hi Alexander,

Yes, because the AEMIF module is operating at half of the module source clock, the DM36x AEMIF clock is referenced as PLL1SYSCLK4/2. Since the maximum PLL1SYSCLK4 is 135Mhz, the maximum AEMIF clock is 67.5Mhz . The example on page 43 and 51 in AEMIF UG is incorrect.

We will correct the false information from the example soon.

Thanks,

Tai Nguyen

0 Alexander Khvilivitzky over 14 years ago in reply to Tai Nguyen

Expert 1055 points

Tai,

What about synchronous mode - is it possible to run EMIF at 66MHz clock as the data sheet says? Are there any limitations to that?

Thanks,

Alexander.

0 Tai Nguyen over 14 years ago in reply to Alexander Khvilivitzky

TI__Expert 5955 points

Hi Alexander,

Sorry for the delay, I was off for two days.

At maximum AEMIF input clock frequency (135Mhz), you should be able to run EMIF in synchronous mode at 66Mhz clock. There are no limitations that I am aware of.

Thanks,

Tai

0 Alexander Khvilivitzky over 14 years ago in reply to Tai Nguyen

Expert 1055 points

Tai,

for DM368 max peripheral bus and EDMA clock is 170 MHz. Does it mean EMIF in sync mode could run at 85 MHz on this chip? The data sheet is still showing 66 MHz.

Thanks,

0 Tai Nguyen over 14 years ago in reply to Alexander Khvilivitzky

TI__Expert 5955 points

Hi Alex,

Yes, for the DM368-432 device, the max peripheral bus and EDMA clock is 170Mhz and that means the EMIF can run up to half of the speed which is 85Mhz on this chip. I will ask our app person to update the data sheet.

Thanks for correcting the error,

Tai

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Max EMIF clock???