F021FLASHAPI: Valid wait value for Fapi_initializeAPI()

Chen-Chih Liu

Dear experts,

I'm using the F28P650DK9-ZEJ (EVB) with F021 version 3.00.01.00 for my application.

After invoking Fapi_initializeAPI(0x57000, 200u), it returns the error code Fapi_Error_InvalidHclkValue if my RWAIT is not configured to 4.

I would like to understand why this function returns Fapi_Error_InvalidHclkValue when RWAIT is set to a value larger than 4. According to the user manual, this error code indicates that FCLK is above the maximum FCLK value. However, my understanding is that if RWAIT is larger, the FCLK should be slower, and therefore, this error code should not be displayed.

Note: I configure the SYSCLK to 200MHz.

(I have also used the TI demo project, flashapi_ex1_programming, to confirm. Indeed, if I change RWAIT to 5, this API returns Fapi_Error_InvalidHclkValue.)

Thanks and regards,

C.C.Liu

over 1 year ago

0 Vamsi Gudivada over 1 year ago

TI__Guru* 87155 points

Hi C.C.Liu,

We characterize the flash programming for the best performance frequency and wait-state combination; and not at all the wait-state possibilities. Hence, we allowed only the below range:

Thanks and regards,

Vamsi

0 Chen-Chih Liu over 1 year ago in reply to Vamsi Gudivada

Intellectual 340 points

Hello Vamsi,

Thanks for your reply.

Since other devices, such as the 28377, do not have this limitation, and according to your screenshot, there is a minimum requirement rather than just one configuration, correct?

May I know if this restriction only applies to the F28P65X and is limited by the F021 code?

Thanks and regards,

C.C.Liu

+1 Vamsi Gudivada over 1 year ago in reply to Chen-Chih Liu

TI__Guru* 87155 points

Hi C.C.Liu,

We allow only above combinations. Example: 80 to 120MHz allows RWAIT of 2.

We followed this in F280013x, F280015x, F28P65x and F28P55x devices.

Thanks and regards,

Vamsi

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F021FLASHAPI: Valid wait value for Fapi_initializeAPI()