GPMC Timing Parameters for Asynchronous Single Write - AM335x.

ARM arm

Hi,

Query 1:-

We want to know as to what is the frequency of GPMC_FCLK? Is it 100MHz or 104MHz and whether it changes to some other value during ROM boot loader? The reason is we want to compute GPMC timing parameters accurately for which we require this.

Query 2:-

We have gone through TRM AM335X, Table 7-48. GPMC Timing Parameters for Asynchronous Single Write and there we find WeOnTime = 3ns whereas the WEONTIME = 1 which means 1 GPMC_FCLK i.e. order of 10ns. Why it is so? Is it an error in the document? Again WeOffTime is shown as :- tCS + tWP + tWPH = 3ns + 25ns + 20ns. Where as Figure 7-47 in TRM, it shows WeOffTime = tCS + tWP = 20ns + 30ns. I think 3ns is wrong perhaps and rest are relative w.r.t what configuration values are chosen... please revert.

Query 3:-

How can I control these GPMC parameters when I want to flash the NOR which will hold my application code? I do not know how to do this.

Regards.

over 10 years ago

0 Biser Gatchev-XID over 10 years ago

TI__Guru**** 393215 points

Hi,

Q1 The GPMC_FCLK frequency is 100MHz. This is what ROM code sets it to.

Q2 Obviously 1 GPMC_FCLK cycle is the closest you can get to the required time of 3ns.

I cannot help on your third question.

0 ARM arm over 10 years ago in reply to Biser Gatchev-XID

Expert 2630 points

Hi Biser,

Why 3ns is at all required? From where this value come from of 3ns?

Where shall we look for the 3rd question as this will solve our lot of trouble..

0 ARM arm over 10 years ago in reply to ARM arm

Expert 2630 points

You mean to say that the values in Table 7-48 are the minimum time coming from hardware for which GPMC interface will work. Is it the meaning?

0 Biser Gatchev-XID over 10 years ago in reply to ARM arm

TI__Guru**** 393215 points

MOHIT HADA said:
Why 3ns is at all required? From where this value come from of 3ns?

Read before the table: Table 7-48 shows the timing parameters (on the memory side) that determine the parameters on the GPMC side.

MOHIT HADA said:
Where shall we look for the 3rd question as this will solve our lot of trouble..

Check this wiki: http://processors.wiki.ti.com/index.php/Sitara_Linux_AM335x_Flash_Programming_Linux_Development

0 ARM arm over 10 years ago in reply to ARM arm

Expert 2630 points

Ok this is a sample example for a memory :- Table 7-48 shows the timing parameters (on the memory side)

understood...

Kindly tell us where to look for controlling the parameters of GPMC while flashing NOR so that we can work as per our designed PCB in a hassle free manner during Flashing..

0 Biser Gatchev-XID over 10 years ago in reply to ARM arm

TI__Guru**** 393215 points

MOHIT HADA said:
Kindly tell us where to look for controlling the parameters of GPMC while flashing NOR so that we can work as per our designed PCB in a hassle free manner during Flashing..

Look at the wiki in my post above and describe more clearly how you intend to flash the memory, what software and which version you are using?

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GPMC Timing Parameters for Asynchronous Single Write - AM335x.