I don’t own one. So I’ve put in a query to R&D.
Sent from my iPhone > On Jun 14, 2021, at 11:22 AM, Jim Palladino <j...@gardettoengineering.com> > wrote: > > > Hi Marcus, > > What is the best way to check the hardware revision? I don't have one in > front of me, but one of the other engineers checked the label on a N320 and > doesn't see a revision letter (at least it isn't obvious if it's there). Or > can this be checked with uhd_usrp_probe. The only thing we see there is: > > | | rev: 10 > > Thanks, > Jim > > From: Marcus Müller <marcus.muel...@ettus.com> > Sent: Friday, June 11, 2021 3:07 PM > To: Marcus D. Leech <patchvonbr...@gmail.com>; Jim Palladino > <j...@gardettoengineering.com>; usrp-users@lists.ettus.com > <usrp-users@lists.ettus.com> > Subject: Re: [USRP-users] Re: N320 1PPS input voltage > > Hi Jim, > > The congregation of Marcuses checked with R&D, and we figured out that in > fact, the > NC7SV157 in U24 was replaced by a SN74LVC2G34, which is OK up to 6.5 V input, > in Hardware > revisions starting with Rev C. > > So, if (and only if) you have a N320 in a revision that's C or greater, > you're safe. > Otherwise, please don't connect a 5V source to the PPS input for now. > > Best regards, > > Marcus > > > On 11.06.21 15:58, Marcus D. Leech wrote: > > On 06/11/2021 09:45 AM, Jim Palladino wrote: > >> Hi Marcus, > >> > >> Right -- the output of the Octoclock is 5V. I'm not seeing how the N320 > >> can accept that > >> as an input. The knowledge base article says the N320 expects 5Vpp at the > >> 1pps input. > >> But the schematics/parts data sheet for the input buffer don't seem to > >> support that . . > >> . unless I'm missing something. > >> > >> Thanks, > >> Jim > > It certainly looks like a potential problem, but I haven't heard of anyone > > having 1PPS > > failure issues on the N320 when used with > > Octoclock--pretty sure it was tested with Octoclock prior to release. > > But I'll check > > with R&D. > > > > > >> > >> ------------------------------------------------------------------------------------------ > >> *From:* Marcus D. Leech <patchvonbr...@gmail.com> > >> *Sent:* Friday, June 11, 2021 9:39 AM > >> *To:* usrp-users@lists.ettus.com <usrp-users@lists.ettus.com> > >> *Subject:* [USRP-users] Re: N320 1PPS input voltage > >> > >> On 06/11/2021 09:11 AM, Marcus Müller wrote: > >> > Hello Jim, > >> > > >> > > >> > hm, that knowledge base article must be wrong: The octoclock internally > >> > only has a 3.3V > >> > supply. But before I say something wrong here, let me check back. > >> > > >> > > >> > Best regards, > >> > > >> > Marcus > >> The 1PPS outputs on the Octoclock are bufered by 7404 inverters, which > >> appear to have a 5V Vcc. > >> > >> > > >> > > >> > On 11.06.21 14:17, Jim Palladino wrote: > >> > > >> >> Hello, > >> >> > >> >> We are planning on using an octoclock with several devices, including > >> >> an N320. The > >> >> octoclock outputs a 5V 1pps signal, but I'm confused about the N320 > >> >> 1pps input. > >> >> > >> >> According to > >> (https://urldefense.proofpoint.com/v2/url?u=https-3A__kb.ettus.com_N320_N321-29-3A&d=DwIF-g&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=XUEEtUEfpaAEGxRI-WGuqHauOvsPdD2NZkfwDnwpYx0&m=-9vS_HYCWF4BKKIX7QR3SO2LJ3yD1MyEElYsX5a8WMs&s=TdFHQJNItGehIsL1D4yXezIfq_vO05AvF1_lMSyNpHs&e= > >> >> "PPS - Pulse Per Second Using a PPS signal for timestamp > >> >> synchronization requires a > >> >> square wave signal with the following a 5Vpp amplitude." > >> >> > >> >> If I look at the schematics for the N320, on page 15, > >> >> > >> (https://urldefense.proofpoint.com/v2/url?u=https-3A__kb.ettus.com_images_f_f4_USRP-5FN3XX-5FMB-5FSchematic.pdf&d=DwIF-g&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=XUEEtUEfpaAEGxRI-WGuqHauOvsPdD2NZkfwDnwpYx0&m=-9vS_HYCWF4BKKIX7QR3SO2LJ3yD1MyEElYsX5a8WMs&s=6JTHdP9IoYFRQhn24LgJjEofkuFwgAsHTs9iHhgMuBg&e= > >> <https://urldefense.proofpoint.com/v2/url?u=https-3A__kb.ettus.com_images_f_f4_USRP-5FN3XX-5FMB-5FSchematic.pdf&d=DwIF-g&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=XUEEtUEfpaAEGxRI-WGuqHauOvsPdD2NZkfwDnwpYx0&m=-9vS_HYCWF4BKKIX7QR3SO2LJ3yD1MyEElYsX5a8WMs&s=6JTHdP9IoYFRQhn24LgJjEofkuFwgAsHTs9iHhgMuBg&e=>) > >> they show that the input > >> >> 1pps signal goes through an NC7SV157. Vcc for that is 3.3V in the > >> >> schematics. > >> >> > >> >> According to the datasheet, the absolute maximum rating on the input is > >> >> 4.3V. > >> >> > >> "https://urldefense.proofpoint.com/v2/url?u=https-3A__www.onsemi.com_pdf_datasheet_nc7sv157-2Dd.pdf&d=DwIF-g&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=XUEEtUEfpaAEGxRI-WGuqHauOvsPdD2NZkfwDnwpYx0&m=-9vS_HYCWF4BKKIX7QR3SO2LJ3yD1MyEElYsX5a8WMs&s=XPmiCDRDfM2wVtI1g4KChC9dkOJhMyrqBTMv_Rx01Xg&e= > >> <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.onsemi.com_pdf_datasheet_nc7sv157-2Dd.pdf&d=DwIF-g&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=XUEEtUEfpaAEGxRI-WGuqHauOvsPdD2NZkfwDnwpYx0&m=-9vS_HYCWF4BKKIX7QR3SO2LJ3yD1MyEElYsX5a8WMs&s=XPmiCDRDfM2wVtI1g4KChC9dkOJhMyrqBTMv_Rx01Xg&e=>" > >> >> > >> >> So, I'm not sure how the N320 can safely accept a 5V input (from the > >> >> octoclock or other > >> >> device). > >> >> > >> >> Thanks, > >> >> Jim > >> >> > >> >> > >> >> _______________________________________________ > >> >> USRP-users mailing list -- usrp-users@lists.ettus.com > >> >> To unsubscribe send an email to usrp-users-le...@lists.ettus.com > >> > _______________________________________________ > >> > USRP-users mailing list -- usrp-users@lists.ettus.com > >> > To unsubscribe send an email to usrp-users-le...@lists.ettus.com > >> _______________________________________________ > >> USRP-users mailing list -- usrp-users@lists.ettus.com > >> To unsubscribe send an email to usrp-users-le...@lists.ettus.com > > > > > > _______________________________________________ > > USRP-users mailing list -- usrp-users@lists.ettus.com > > To unsubscribe send an email to usrp-users-le...@lists.ettus.com
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