Calculate GPMC Timings for Nand-Flash

Zenz:

Just follow the datasheet of  the nand flash, according to that set all gpmc registers!

Go through the gpmc registers explaination!

Regards,

santosh vastrad

Thank You for your reply.

I have some trouble to match the timings from the nand-flash datasheet with the gpmc registers! Is it possible to get some help here? For example a mapping sheet.

Zenz:

Check out the below link!

Helpful!!!!!!!!!!!!!!

http://e2e.ti.com/support/dsp/omap_applications_processors/f/42/t/30244.aspx#105441

Regards,

santosh vastrad

Thank you again,

but how can i fit this timings from the nand-flash datasheet for example:

Command, Data, and Address Input (1.8V)

ALE to data start    tADL 70  ns
ALE hold time        tALH 5 ns  
ALE setup time      tALS 10 ns  
CE# hold time        tCH 5 ns  
CLE hold time        tCLH 5 ns  
CLE setup time      tCLS 10 ns  
CE# setup time      tCS 20 ns  
Data hold time       tDH 5 ns  
Data setup time     tDS 10 ns  
WRITE cycle time  tWC 25 ns
WE# pulse width HIGH tWH 10 ns
WE# pulse width   tWP 12 ns
WP# transition to WE# LOW  tWW 100 ns

into the values of the gpmc registers.

Read Cycle and Write Cycle are available, but for example i am not sure if CS_ONTIME equals CE# hold time.

I hope you understand my problem. The information of your link does not help me in this case.

If i would have the data like this

        //CS = 50nsec 0-50ns    ----|__________|--------
        //RD cycle time = 55ns
        //WR cycle time = 55ns
        //OE = 40ns   5-45ns    -----|________|---------
        //WR = 40ns   5-45ns    -----|________|---------
        //RD acsess time = 45n
        //WR acsess time = 45n

for our nand-flash it would be no problem to find the right register values.

Thank You

Zenz:

what i sent link have your requirment just look once again!!!!!!!!!!!!!

Regards,

santosh vastrad

Hello,

i think that i am still had no success to tell you how my problem looks like.

So i made the following assignment. The  value-names with capital letters stand for parts of the GPMC-Registers, the value-names at the end of the lines are taken from the datasheet.

CS_OFFTIME_VAL = 25nsec = 20ns + 5ns = #CE setup time + #CE hold time

ADVRDOFFTIME_VAL = ADVWROFFTIME_VAL =  = CS_RD_OFFTIME_VAL = CS_WR_OFFTIME_VAL = CS_OFFTIME_VAL

CS_ONTIME_VAL = 0

RD_CYCLE_TIME_VAL = 25ns    = READ Cycle Time

WR_CYCLE_TIME_VAL = 25ns = WRITE Cycle Time

WR_ONTIME_VAL = OE_ONTIME_VAL  = 8ns =  20ns-12ns = CE# setup time - RE# pulse width

WR_OFFTIME_VAL = OE_OFFTIME_VAL  = 20ns =  20ns = CE# setup time

WR_ACCESS_TIME_VAL = RD_ACCESS_TIME_VAL = 22n = CE# Access Time

When i setup the GMPC - Registers with this values it does not work. Where are my mistakes?

I  there is no post at the thread on which your pointing to which does show the answer to my problem.

Thank You

Zenz:

you added all these values in gpmc registers, okay!

IN U-boot code you are making changes for gpmc registers or using flashtool for flashing an  images into the nand!

Just cleariy on this matter!

Regards,

santosh vastrad

I am making this changes in the u-boot code. I have already a set of gpmc register values that does work but i think this set is not optimal concerning performance/timings.

So what I want to do is to find the timings that fit to our nand-flash best.

Thank You!