QSPI interface with MMC : some problems

Hi all,

I have problem reading an MMC card.

I have the MISO signal  coming from the MMC as
follows.

http://www.geocities.com/qspimmc/miso_signal.jpg


Here are my questions:


1)
I am using QSPI ( SPI) and Im not sure how to
interpret this signal which is above. Is the MISO
signal defective on the MPC555 side?

Im running the CLK at 143khz , Im using a level
translator MAx3002E to match different voltages of the
MMC and my host controller 

The mmc is at 3.3 V  and my micrcontroller is at 5 V.

THe interface is achieved with the level translator.

Can anyone tell me if there is anything wrong in the
MISO signal?

2)
I want to disable the queue and intialize the MMC . I
read the QSMCM manual but there is no explicit way of
having only one instruction in the Recieve ram or the
transmit ram which can be used for SPI communication.

Is it necessary that we have to intialize the queue,
the transmit and Recieve Ram to start using the QSPI
module ? Can we use the queue pointers to use limit
the   number of entries in the Transmit buffer which
can be transmitted?

For example , we have 32 entries for Command ram , 64
each for Transmit and recieve ram

I want to create functions which can send "one" byte
over the SPI channel 

but with the queue, it seems necessary that I have to
intialize all entries before I start the QSPI . Is
there any way of doing it without intializing the
queue  with a set of values , rather than  adding
entries to the QUEUE one at a time when we want to
send/ receive information?


3)
Is it possible that we can write entries in the
Transmit RAM and recieve bytes in the Recieve Ram at
Runtime ? i.e when the QSPI is running ( assuming WRAP
around mode is used).



4) IS it necessary that we have to use pull up
resistors on the MISO and MOSI signals on the MMC side
of the elctrical interface? If so, what are the ideal
values of the pull up resistors?


Thanks in advance.




	
		
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