Changes between Version 44 and Version 45 of wireless/modem


Ignore:
Timestamp:
06/11/2019 11:00:02 PM (5 weeks ago)
Author:
Ryan Erbstoesser
Comment:

add information about masking and resistors

Legend:

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  • wireless/modem

    v44 v45  
    6161[=#conflicts]
    6262== Pin Signal and Voltage Conflicts ==
     63
     64Mini-PCIe modems will use USB signals on the Mini-PCIe slot to communicate with the single board computer (SBC).
     65
    6366Many modems do not follow the Mini-PCIe pin specification.
    6467
    6568Gateworks designs the Mini-PCIe slots to strictly adhere to the formal specification by PCI SIG.
     69
     70Most of the Mini-PCIe slots on Gateworks SBCs have PCIe signalling routed to them which can cause conflicts for modems but are required for regular WiFi cards (802.11a/b/g/n/ac). However, there are some slots that do not have PCIe signalling and USB only. Typically these USB only slots are ideal for modems. These exist on some products such as the GW5220, GW6400, among others. Consult the white silkscreen lettering on the PCB board next to the Mini-PCIe slot to see what signalling is routed.
    6671
    6772Thus Gateworks typically find pin conflicts (signal mismatch or voltage differences) on the following pins:
     
    7782Please compare the modem pinout to the Gateworks pinout to ensure compatibility.
    7883
    79 Some Gateworks SBCs have special resistor loading to eliminate some of these conflicts. Please contact Gateworks support (support at gateworks.com) to learn more.
     84Some Gateworks SBCs have special resistor loading to eliminate some of these conflicts. Please contact Gateworks support (support at gateworks.com) to learn more. See an example image below depicting resistors that can be unloaded to disconnect certain signals.
     85 * [[Image(modemresistors.png)]]
     86
     87For prototype testing, conflicting pins on the modem can be blocked with masking tape (see below picture). Once validated, resistor loading can sometimes be adjusted to eliminate the conflicting signals. Contact Gateworks to discuss unloading these resistors.
     88 * [[Image(modem-tape-small.png)]]
     89
    8090
    8191