Re: Legacy memstick support + FTL questions

[Alex Dubov <oakad@yahoo.com>]

> > 
> > It is quite possible. Some controllers will
> automatically retrieve an
> > "interrupt" field from the status register on each
> media access (in fact,
> > this behavior is mandated in parallel mode). Check if
> the bits fit "inter-
> > rupt" register bits.
> Doesn't seem to map to anything.
> 
> 
> 
> 
> 0x10 is polled on register writes
> 0x20 is polled on command writes, and then 0x10 is polled
> 0x50 (0x40 | 0x10) if polled after MS_TPC_GET_INT and only
> it
> 
> 0x03 is mask for error detection, if found in any of above
> polls, error
> out.
> 
> The above was for register #19 (0xXX000000) 

So, it's probably an implementation specific register.
There's no common standard for MS interfaces.

> 
> after the MS_TPC_READ_LONG_DATA, 0x40 is polled, and
> register #18 is
> polled for 0x20 clear. These are all bits that are
> accessed.
> 
> You try to tell me that controller itself issues TPCs,
> reads their
> responses, and puts that in registers, right? This is very
> interesting.
> 
> Bus is half duplex, and there is a line that indicates who
> sends data.
> 
> I currently understand that host sends an TPC, then card
> sends a
> response. Is it another TPC?


Not at all.
I answered this already.
See below.

> > > As I understand it, TPCs are send in both
> directions, and
> > > nothing more.
> > > There are no dedicated lines, or something like
> that.
> > 
> > TPC means "transport protocol command" and it is only
> send from host to
> > media. Generally speaking, the whole thing works like
> this (each point
> > is a TPC):
> > 
> > 1. Host selects media register access window.
> > 2. Host modifies media register values.
> > 3. Host invokes media command.
> > 4. Host reads media registers.
> > 5. Host moves data around.
> > 6. Lather, rinse, repeat.
> 
> > 
> > > 
> > > So status should be a content of the answer TPC
> or
> > > something like that.
> > 
> > It is not.
> > 

Legacy MS protocol uses 3 meaningful lines: SCLK (clock), SDIO (data/
command IO) and BS (bus state lane). There may be additional 3 or 7
DIO lines but they are only used for bulk data transfer.

There are 4 hw states:

1) BS at low - media is idle
2) BS goes to high - TPC is clocked in on SDIO
3) BS goes to low - host waits for level change on SDIO
4) BS goes to high - data can be clocked in/out on all data lines
5) BS goes to low again -> same as 1 (idle)

Media can not initiate anything and can not send anything to host.
Host is responsible to query the media state as necessary.

> > > I wish I had the memstick spec (original not
> pro)
> > > 
> > 
> > There's an email address on Sony's website.
> And the chances they give me the specs without NDA and a
> lump of money
> are higher that winning a lottery?
> 

They will give you the spec for nothing if you're a certified sony
developer. How do you become one is different question, but it is not
money dependent.



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