No there are not. That is why I am saying you need them on the expansion board. The reason there is no buffer on the board is because it had to be cheap and fit in an Altoids box. I could not do that and add the buffer,
By buffers I mean like the one used on the LCD board. https://github.com/CircuitCo/BeagleBone-LCD7-RevA3/blob/master/BeagleBone-LCD7-RevA3-schematic.pdf?raw=true Look at U1. Replace the VDD_LCD with 1.8V. Gerald On Wed, Oct 8, 2014 at 1:48 PM, Bremenpl <[email protected]> wrote: > I am only asking, no hard feelings :p. Ive just noticed that there were > no buffers on the lcd lines between nxp and mcu on the bbb. Thats why I > asked. Why are there no buffers on the bbb? By buffers do you mean that a > voltage follower would do if the inputs are 3.3V tollerant? > > Dnia 8 października 2014 20:44:37 Gerald Coley <[email protected]> > napisał(a): > >> It already is powered from 1.8V. The processor however, is powered from >> 3.3V. The NXP part is 3.3V tolerant. >> >> You need the buffer to clean up the signals and provide better drive as >> is being done on the LCD boards.. >> >> I just designed the BeagleBone Black. You are designing your mother board >> so do as you see fit. >> >> Gerald >> >> >> On Wed, Oct 8, 2014 at 1:37 PM, Bremenpl <[email protected]> wrote: >> >>> Cant I just power the NXP from 1.8V? If the lines are 1.8V I would >>> need no translation then. Also there are no buffer on the bbb itself so why >>> would I need such? >>> >>> Dnia 8 października 2014 20:12:06 Gerald Coley <[email protected]> >>> napisał(a): >>> >>>> It is the low voltage level as these are 1.8V inputs. The issue is >>>> making sure you get low enough, fast enough due to capacitance and at the >>>> correct frequency to yield a good data integrity. You can try using a >>>> translator buffer from 3.3V to 1.8V. That should help. >>>> >>>> >>>> Gerald >>>> >>>> >>>> On Wed, Oct 8, 2014 at 12:55 PM, Bremenpl <[email protected]> wrote: >>>> >>>>> I could do buffers as well, thats not a problem. I am building the >>>>> board from scratch. Besides, arent the nxp input very high impedance? >>>>> >>>>> Dnia 8 października 2014 19:52:48 Gerald Coley <[email protected]> >>>>> napisał(a): >>>>> >>>>>> I am talking about you adding two NXP parts on those lines as you >>>>>> indicated that you were doing. LCD cape uses buffers do boost the signal. >>>>>> The NXP pins are 1.8V inputs. >>>>>> >>>>>> Gerald >>>>>> >>>>>> On Wed, Oct 8, 2014 at 12:38 PM, Bremenpl <[email protected]> wrote: >>>>>> >>>>>>> There are resistors on the lines, worse case scenarion I can take >>>>>>> them off. But tgose lines are used for lcd cape already so it does work, >>>>>>> whats the problem? >>>>>>> >>>>>>> Dnia 8 października 2014 19:06:54 Gerald Coley < >>>>>>> [email protected]> napisał(a): >>>>>>> >>>>>>>> I doubt it will work but you are free to try. Adding two loads such >>>>>>>> as that on those pins is asking for trouble. >>>>>>>> >>>>>>>> Gerald >>>>>>>> >>>>>>>> >>>>>>>> On Wed, Oct 8, 2014 at 1:50 AM, bremenpl <[email protected]> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> Hello there, >>>>>>>>> I am currently working on a motherboard for the BeagleBone Black. >>>>>>>>> One of the requiments is to have a HDMI output on the side of the >>>>>>>>> motherboard. I Know that there are LCD pins on the BeagleBone Black >>>>>>>>> header >>>>>>>>> and there is a possibility to connect a LCD cape. I was wondering >>>>>>>>> either it >>>>>>>>> would work to duplicate the NXP HDMI framer circuit that is on the >>>>>>>>> board to >>>>>>>>> the motherboard and use it for hdmi output? If I am correct the only >>>>>>>>> difference would be that there is no acces to I2C0 from headers so I >>>>>>>>> would >>>>>>>>> have to use I2C1/2 for the NXP chip. That way at least I wont chave to >>>>>>>>> worry about addressing 2 chips at once (not sure If you can change >>>>>>>>> address >>>>>>>>> of the hdmi framer yet). >>>>>>>>> >>>>>>>>> My question is, would this solution be bard to implement in >>>>>>>>> software, or is it easy to change the I2C bus config for hdmi? Are >>>>>>>>> there >>>>>>>>> any obstacles that I am not aware of? I would really aprichiate any >>>>>>>>> help in >>>>>>>>> here. >>>>>>>>> >>>>>>>>> -- >>>>>>>>> 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 [email protected]. >>>>>>>>> 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 a topic in >>>>>>>> the Google Groups "BeagleBoard" group. >>>>>>>> To unsubscribe from this topic, visit >>>>>>>> https://groups.google.com/d/topic/beagleboard/85MgiQg0wJY/unsubscribe >>>>>>>> . >>>>>>>> To unsubscribe from this group and all its topics, send an email to >>>>>>>> [email protected]. >>>>>>>> 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 [email protected]. >>>>>>> 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 a topic in >>>>>> the Google Groups "BeagleBoard" group. >>>>>> To unsubscribe from this topic, visit >>>>>> https://groups.google.com/d/topic/beagleboard/85MgiQg0wJY/unsubscribe >>>>>> . >>>>>> To unsubscribe from this group and all its topics, send an email to >>>>>> [email protected]. >>>>>> 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 [email protected]. >>>>> 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 a topic in the >>>> Google Groups "BeagleBoard" group. >>>> To unsubscribe from this topic, visit >>>> https://groups.google.com/d/topic/beagleboard/85MgiQg0wJY/unsubscribe. >>>> To unsubscribe from this group and all its topics, send an email to >>>> [email protected]. >>>> 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 [email protected]. >>> 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 a topic in the >> Google Groups "BeagleBoard" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/beagleboard/85MgiQg0wJY/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> [email protected]. >> 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 [email protected]. > 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. 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