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From: urefowei on 17 Dec 2008 06:34
we are doing a thesis on a flash to flash bridge
This project aims to develop microcontroller-based device that can handle
data transfer from a USB storage-device directly to another USB
storage-device. The previous project's device transferring capabilities
were limited in terms of data size, file types, and transfer rate.

we are currently using PIC184550 as our MCU and the MAX3421E as the host
controller..

Looking at Figure 21 (MAX3421E in a Host Application) of MAX3421E DS (page
26),we could not connect SS and GPX, SPI serial slave output and interrupt
pin, respectively, to our PIC..

What can we do about this??
Can we supplement other IO pins on our PIC for these purpose??


From: Andrew Jackson on 17 Dec 2008 14:22
urefowei wrote:
> we are doing a thesis on a flash to flash bridge
> This project aims to develop microcontroller-based device that can handle
> data transfer from a USB storage-device directly to another USB
> storage-device. The previous project's device transferring capabilities
> were limited in terms of data size, file types, and transfer rate.
>
> we are currently using PIC184550 as our MCU and the MAX3421E as the host
> controller..
>
> Looking at Figure 21 (MAX3421E in a Host Application) of MAX3421E DS (page
> 26),we could not connect SS and GPX, SPI serial slave output and interrupt
> pin, respectively, to our PIC..
>
> What can we do about this??

You could use a chip that has the MSSP module in it (e.g. 18F2458,
18F4553). [Use the Microchip website's product selector to find a PIC
with the right peripherals]

> Can we supplement other IO pins on our PIC for these purpose??

You can do SPI communications by bit-bashing but it will be slow. There
are countless examples of this around.

Andrew
From: urefowei on 18 Dec 2008 01:08
>urefowei wrote:
>> we are doing a thesis on a flash to flash bridge
>> This project aims to develop microcontroller-based device that can
handle
>> data transfer from a USB storage-device directly to another USB
>> storage-device. The previous project's device transferring
capabilities
>> were limited in terms of data size, file types, and transfer rate.
>>
>> we are currently using PIC184550 as our MCU and the MAX3421E as the
host
>> controller..
>>
>> Looking at Figure 21 (MAX3421E in a Host Application) of MAX3421E DS
(page
>> 26),we could not connect SS and GPX, SPI serial slave output and
interrupt
>> pin, respectively, to our PIC..
>>
>> What can we do about this??
>
>You could use a chip that has the MSSP module in it (e.g. 18F2458,
>18F4553). [Use the Microchip website's product selector to find a PIC
>with the right peripherals]
>
>> Can we supplement other IO pins on our PIC for these purpose??
>
>You can do SPI communications by bit-bashing but it will be slow. There

>are countless examples of this around.
>
> Andrew
>


We were advised to have two connections in one pin. Is that possible??
for example... >>> connecting a single PIN33 of PIC18 with an external
interrupt 0 and SDI to pin17 (GPX) and pin15 (MISO)MAX3421.
From: Andrew Jackson on 18 Dec 2008 02:13
>>> Can we supplement other IO pins on our PIC for these purpose??
>> You can do SPI communications by bit-bashing but it will be slow.

> There are countless examples of this around.
>
>
> We were advised to have two connections in one pin. Is that possible??
> for example... >>> connecting a single PIN33 of PIC18 with an external
> interrupt 0 and SDI to pin17 (GPX) and pin15 (MISO)MAX3421.

You need to draw a list of pins on each component and then look at each
of their datasheets to see what can be shared. Some pins it won't make
sense to share (while it might be possible to share them in terms of
hardware it might lead to impossibly difficult software). Think about
your requirements for each component.

Andrew
From: urefowei on 18 Dec 2008 02:24

>You need to draw a list of pins on each component and then look at each

>of their datasheets to see what can be shared. Some pins it won't make
>sense to share (while it might be possible to share them in terms of
>hardware it might lead to impossibly difficult software). Think about
>your requirements for each component.
>
> Andrew
>

we actually considered Figure 21 (MAX3421E in a Host Application) on page
26 of MAX3421E DS for our application..
are we doing it right?? we hope to finish our project before the end of
march next year.. thank you for your kind followups.
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