On Wednesday, August 31, 2011 23:45:57 Mike Frysinger wrote: > On Wednesday, August 31, 2011 23:36:39 Jie Zhang wrote: > > On Wed, Aug 31, 2011 at 10:25 AM, Mike Frysinger wrote: > > > On Wednesday, August 31, 2011 09:57:33 Jie Zhang wrote: > > >> From your explanation, the name HWAIT has nothing to do with flash. It > > >> seems to me that it's just a coincidence BF527 SDP board uses PG0 as > > >> flash_enable signal and PG0 happens to be a HWAIT signal for UART. > > > > > > the bootrom has one HWAIT signal and it gets used regardless of boot > > > mode. so you're right in that it isn't specific to any boot source. > > > > > > however, it is not coincidental that the SDP guys picked PG0 to select > > > > > > the flash ... they did it explicitly because the default HWAIT signal > > > is PG0. thus their flash gets selected while the bootrom is booting > > > the LDR, and then gets deselected after everything is done. that way > > > the async pins are free while it's running. > > > > OK. Maybe it's not so coincidental. I still think renaming HWAIT to > > FLASH_ENABLE will be better. What if later boot rom code chooses > > another signal for the same purpose? > > considering the glacial pace bootroms develop, i dont think it's necessary > to plan for something that has a high chance of never happening. > > also, all of the bootrom documentation talks about HWAIT settings in the > LDR files. i think it's best we match what we have now.
also, the current HWAIT usage is designed to act like the bootrom ... it asserts/deasserts based on when the bootrom would if you wanted an option to "select the flash", there's a bunch of existing keys in bus_driver.h already that you could pick from without losing/changing the meaning of HWAIT -mike
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