>
> *Normally SPI's are good up to 100MHz, but this is seldom needed. I
> normally set them up at 1MHz for initial debug (allows for cheaper
> instruments) and then usually go to 10MHz which normally makes speed a
> non-issue and allows for longer wires. 16MHz should be fine as well. I2C's
> often run around 1MHz and are very dependent on length (i.e. capacitance).
> One needs to keep I2Cs high when not used to minimize power due to
> pull-ups. SPI's, once you get them going, are generally a better choice.*
>
SPI through the PRU seems to be limited at around 21.2Mhz. At least an
implementation I was just reading about. It seemed that the author was bit
banging however. Using the other PRU core for the clk timer as well.
On Wed, Dec 16, 2015 at 12:49 PM, Robert Nelson <robertcnel...@gmail.com>
wrote:
> > Currently I'm fighting with WiFi; I had scripts to detect the wlanx
> device
> > using iw dev | grep "Interface" | awk '{printf $2}' but this is failing
> at
> > boot; it works fine after boot. I tried hard coding the wlanx device, but
> > now it seems to change; when I specify wlan0, it comes up as wlan1, and
> vice
> > versa? It seems wireless networking changed somewhat from my previous
> > version, and I haven't tracked down what yet. So wireless first, apt-gets
> > second, pips third, device trees fourth, prus fifth, and then tracking
> down
> > why previously debugged software stopped working. It might be
> interesting to
> > keep track of how many issues come up.
>
> Sounds like the wifi device has a mac that changes..
>
> Right a udev rule to push it back to wlan0..
>
> here's an example of a udev rule we used on teh bbb's for the eth0:
>
>
> https://eewiki.net/display/linuxonarm/BeagleBone+Black#BeagleBoneBlack-Networking:UsingasharedSDcardwithMultipleBeagleBone
>
> For example, enp2s0 on my desktop:
>
> $ sudo udevadm info -a /sys/class/net/enp2s0
>
> Udevadm info starts with the device specified by the devpath and then
> walks up the chain of parent devices. It prints for every device
> found, all possible attributes in the udev rules key format.
> A rule to match, can be composed by the attributes of the device
> and the attributes from one single parent device.
>
> looking at device
> '/devices/pci0000:00/0000:00:15.0/0000:02:00.0/net/enp2s0':
> KERNEL=="enp2s0"
> SUBSYSTEM=="net"
> DRIVER==""
> ATTR{addr_assign_type}=="0"
> ATTR{addr_len}=="6"
> ATTR{address}=="bc:5f:f4:e5:9d:83"
> ATTR{broadcast}=="ff:ff:ff:ff:ff:ff"
> ATTR{carrier}=="1"
> ATTR{carrier_changes}=="1"
> ATTR{dev_id}=="0x0"
> ATTR{dev_port}=="0"
> ATTR{dormant}=="0"
> ATTR{duplex}=="full"
> ATTR{flags}=="0x1003"
> ATTR{gro_flush_timeout}=="0"
> ATTR{ifalias}==""
> ATTR{ifindex}=="2"
> ATTR{iflink}=="2"
> ATTR{link_mode}=="0"
> ATTR{mtu}=="1500"
> ATTR{name_assign_type}=="4"
> ATTR{netdev_group}=="0"
> ATTR{operstate}=="up"
> ATTR{speed}=="1000"
> ATTR{tx_queue_len}=="1000"
> ATTR{type}=="1"
>
> looking at parent device '/devices/pci0000:00/0000:00:15.0/0000:02:00.0':
> KERNELS=="0000:02:00.0"
> SUBSYSTEMS=="pci"
> DRIVERS=="alx"
> ATTRS{broken_parity_status}=="0"
> ATTRS{class}=="0x020000"
> ATTRS{consistent_dma_mask_bits}=="64"
> ATTRS{d3cold_allowed}=="1"
> ATTRS{device}=="0x10a1"
> ATTRS{dma_mask_bits}=="64"
> ATTRS{driver_override}=="(null)"
> ATTRS{enable}=="1"
> ATTRS{irq}=="38"
> ATTRS{local_cpulist}=="0-3"
> ATTRS{local_cpus}=="f"
> ATTRS{msi_bus}=="1"
> ATTRS{numa_node}=="-1"
> ATTRS{subsystem_device}=="0x10a1"
> ATTRS{subsystem_vendor}=="0x1849"
> ATTRS{vendor}=="0x1969"
>
> looking at parent device '/devices/pci0000:00/0000:00:15.0':
> KERNELS=="0000:00:15.0"
> SUBSYSTEMS=="pci"
> DRIVERS=="pcieport"
> ATTRS{broken_parity_status}=="0"
> ATTRS{class}=="0x060400"
> ATTRS{consistent_dma_mask_bits}=="32"
> ATTRS{d3cold_allowed}=="0"
> ATTRS{device}=="0x43a0"
> ATTRS{dma_mask_bits}=="32"
> ATTRS{driver_override}=="(null)"
> ATTRS{enable}=="1"
> ATTRS{irq}=="24"
> ATTRS{local_cpulist}=="0-3"
> ATTRS{local_cpus}=="f"
> ATTRS{msi_bus}=="1"
> ATTRS{numa_node}=="-1"
> ATTRS{subsystem_device}=="0x0000"
> ATTRS{subsystem_vendor}=="0x1022"
> ATTRS{vendor}=="0x1022"
>
> looking at parent device '/devices/pci0000:00':
> KERNELS=="pci0000:00"
> SUBSYSTEMS==""
> DRIVERS==""
>
>
> Regards,
>
> --
> Robert Nelson
> https://rcn-ee.com/
>
> --
> For more options, visit http://beagleboard.org/discuss
> ---
> You received this message because you are subscribed to the Google Groups
> "BeagleBoard" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to beagleboard+unsubscr...@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.
>
--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups
"BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to beagleboard+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
