Read/nBusy via interrupt

Thomas Gleixner tglx at linutronix.de
Fri Oct 29 06:16:18 EDT 2004


On Fri, 2004-10-29 at 19:56 +1000, Aras Vaichas wrote:
> > No. Usually R/B is connected anyway.
> 
> usually? If the software doesn't need it, then why would you connect it?

There's a different between needs it and takes advantage of it. If I can
take advantage, then I will connect it. Using the R/B signal instead of
polling is an advantage.

> >>* more code to write and debug!
> > 
> > About 20 lines. I'm scared.
> 
> No need to be scared. Software engineers don't come for free. development time 
> == money.

Developing efficient polling might need software engineers too. 

> I never said it would affect it significantly (or did I?). I was simply stating 
> the fact that the time does increase. Every pin on a chip costs extra and when 
> you are planning on making 10,000+ per year of a product, that price difference 
> makes a affects your company's bottom line. If you don't believe me, then take 
> a look at the Digikey page for the AT45DB081 and take a long hard look at unit 
> price versus pin count.

I'm aware of high volume designs, where the pin count, pcb size ... has 
to be taken into account.

> Doesn't it count as an MTD device? Where did this kernel option come from -> 
> "CONFIG_MTD_AT91_DATAFLASH" ??

Did I say that ?

> 
> > We are talking about NAND >= 32MB, which is often used for filesystems.
> 
> Ben didn't mention "NAND >= 32MB, which is often used for filesystems", or 
> perhaps I read the initial email incorrectly ... hmmm, my bad. 

Ben was explicitly talking about NAND FLASH, where today the non
obsolete devices start at 32MB

> Thomas, your reply to my email was so ridiculously over the top and harsh. 

Sorry, It was not my intention to offend you. 

> I was simply offering an opinion and some information on a useful MTD device from 
> the position of someone with hardware experience. Perhaps next time you should 
> re-think the tone of your replies and consider the signal-to-noise ratio of 
> what you write. I'm sure this forum will be a better place for it.

Just FYI, I have >20 years hardware/software experience.

Talking about signal/noise ratio. Is an extensive explanation of
DataFlash in answer to a question on NAND FLASH signal or noise ?

tglx






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