Flash controller initialization time

bernard2399 · ‎2006-09-12

Posted on September 12, 2006 at 11:58

bernard2399 · ‎2006-09-05

Posted on September 05, 2006 at 09:54

A note in section 2.3 (Write Operation) of STR7 Flash Programming Reference Manual says that the first write/erase operation makes flash bank0 not accessible.

However, even when looking in section 2.3.3 (Memory Characteristics) of the STR71xF familly, there is no time information for this initialization delay.

My problem is the following:

- I run the flashing from RAM to allow access to either banks.

- the flashing code uses a spin loop to wait for some FLASH_CR0 flags to be cleared. However there is a maximum number of loops to avoid getting stuck in this code if ever there is a problem with the flash controller.

- My target will run at different clock speed, so I must calculate the number of loops dynamically.

- I'm afraid to calcultate a too small value for the first program/erase operation because of this unknown initialization time and give back control to code running in bank 0 too early.

So I need the 'flash procedure' initialization time for ST71xF... Where can I find it?

Thanks!

kleshov · ‎2006-09-12

Posted on September 12, 2006 at 11:58

If there is no official information, you can do the following: measure flash initialization time, multiply by 10 to be safe, then use that value in your code. My rough measurement of initialization time gave a value of a few milliseconds.