External Ram and Nand flash

[larsbayalexande]

Hi Are There anyone who has implemented External ram and the Nand flash as in TWR-60F120M ?

I have implemented on my board external ram like AN4393 figure 5. But when i look at the data for the Nand flash implentation there are some pins that are connected  together.

Lars

[Kan_Li · Accepted solution]

Hi,

K60 120MHz part does implement an arbitration scheme that allows for sharing between the FlexBus and NFC; however, this sharing is really only used for the NFC data lines/FlexBus AD lines and the NFC_WE and FlexBus R/W signals. If you look at the signal muxing table in the manual you can see that these pins only have a single function selection for FlexBus/NFC.  For example, PTB20 function ALT5 is “FB_AD31/NFC_DATA15.” So this is a case where the pin is configured for a FB/NFC mode and dynamically switches between the two.

In the case of the control signal pins (for example,NFC_CE0 and NFC_RB) which have different programmed functions to choose between the FlexBus and NFC signals on the pins, it does not dynamically switch between the functions. It is fixed as a FlexBus or NFC pin based on whether you choose ALT5 or ALT6.

So this means if customer wants to use FB_BE23_16 and FB_BE31_24 to connect external SRAM, then they will not be able to use NAND flash at the same time. As a possible solution, the customer could add a small amount of external logic to decode the lower address lines and use those to generate byte enable signals.

Hope that helps,

B.R

Kan

[williamely]

If I understand the situation correctly, the only NFC pins that do not work with FB arbitration are NFC_RB, NFC_CE0 and NFC_CE1.

The NFC_CLE, NFC_ALE, and NFC_RE pins should work with the dynamic switching.

Is that correct?

[Kan_Li]

Yes, your understanding is correct.

B.R

Kan

[danielchai]

Hi Kan,

I have a TWR-K60F120 and TWR-MEM board. I checked the signal on these boards, it seems only NAND flash use the NFC_RB , NFC_CE0_b, NFC_ALE, NFC_RE. Then it should not conflict. The problem now is that when I plug in the TWR-MEM board and  test the nandflash using the sample code nandflash_twrk60f210m, the writing is fine but the reading always return -1. After I unplug the TWR-MEM and still use the same code to test the nand flash, it works fine.

Do you have any ideas which part can cause this problem?

Thank you.

-Daniel

[Kan_Li]

Hi Daniel,

Please kindly check the J11 and J16 on TWR-MEM, and they should be left unconnected to avoid the interference from the onboard CPLD. My colleague has experienced such issue and solved it with these two jumpers open.

Hope that helps,

Have a great day,
Kan

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