On Thursday 07 January 2021 18:18:52 Peter C. Wallace wrote:
> On Thu, 7 Jan 2021, Ralph Stirling wrote:
> > Date: Thu, 7 Jan 2021 22:05:32 +0000
> > From: Ralph Stirling <ralph.stirl...@wallawalla.edu>
> > Reply-To: "Enhanced Machine Controller (EMC)"
> > <emc-users@lists.sourceforge.net>
> > To: "emc-users@lists.sourceforge.net"
> > <emc-users@lists.sourceforge.net> Subject: [Emc-users] Rpi 3b+ to
> > 7i90hd
> >
> > I have a Raspberry Pi 3b+ successfully talking to a
> > Mesa 7c81, but am now trying to get it working with
> > a 7i90hd. I have a very compact pcb made to go
> > from the 2x20 header on the pi to the 2x13 header
> > on the 7i90hd. It is wired:
> >
> > Signal Rpi 7i90hd
> > SDI 19 13
> > SDO 21 15
> > SCK 23 11
> > SCS 24 17
> >
> > +5V 2,4 26
> > GND 6,9,20,25,30,34,39 10,12,14,16,18,20,22,24
> >
> > My test is:
> > $ mesaflash --device 7i90hd --addr /dev/spidev0.0 --spi --readhmid
> >
> > Response is:
> > unable to set bpw32, fallback to bpw8
> > Unexpected cookie at 0100..0110:
> > 00000000 00000000 00000000
> > No 7I90HD board found
> >
> > Since a 7c81 works, it would seem my software setup is ok.
> > The problem would seem to lie with either my little adapter
> > board or with the 7i90hd. I have a bypass cap right between
> > pins 4 and 6 on the RPi connector (22uF 0805 ceramic). Do
> > I need to use a four layer board to have sufficient ground
> > plane? I have copper pour on the top and bottom of the board,
> > but it did not go between pins of the connectors.
> >
> > Any suggestions?
> >
> > Thanks,
> > -- Ralph
>
> Looks right
>
> 2 layer should be fine as long as the ground is solid (wide)
> between the 7I90 and the RPI (and lo longer than a couple of
> inches
>
> You might try adding a pullup to SDO (7I90 15) to see if you read
> 0xFFFFFFFF which would indicate the the 7I90 is not driving SDO
>
> Sure you have a SPI config in the 7I90?
>
The rpspi driver should handle that.
>
> Peter Wallace
> Mesa Electronics
>
> (\__/)
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> (")_(") signature to help him gain world domination.
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>
>
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