Groups > sci.electronics.design > #519135

Re: tiny board

From	<698839253X6D445TD@nospam.org>
Newsgroups	sci.electronics.design
Subject	Re: tiny board
Date	2018-10-13 06:59 +0000
Organization	Aioe.org NNTP Server
Message-ID	<pps54m$ora$1@gioia.aioe.org> (permalink)
References	(2 earlier) <h7esrdl6ni0gbf3m0iutjn6uambclocetc@4ax.com> <ppliub$hb4$1@gioia.aioe.org> <l7ksrdt7ur1k4br3hh1mdb864f81m8ovn9@4ax.com> <ppqna4$q0c$1@gioia.aioe.org> <vtu1sdp2439fdj9qhut00n6n5d2gded37l@4ax.com>

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John Larkin wrote
>>>On Wed, 10 Oct 2018 19:12:10 GMT, <698839253X6D445TD@nospam.org>
>>>>Been coding a Linux test program for the LMX2332 PLL chip,
>>>>very hard to read datasheet,
>>>>could not register on TI site to download their windows program,
>>>>so writing my own.
>>>
>>>We had to develop c code to drive the LMX2571 synth chip. It has a 62
>>>page data sheet and about 4000 registers, and involves all sorts of
>>>rules and number-theory stuff. 
>>>
>>>TI wasn't any help. They obviously have procedures to go from
>>>frequency to register settings, and they obviously have c code in
>>>their eval kits, and they refused to let us see any of that.
>>
>>I have the software framework running now, hard to find test vectors, 
>>but one thing bugs me in this chip:
>>there is one output pin that seems multiplexed to show different signals in the chip,
>>like outputs from different dividers etc...
>>But in the control registers you can set bits that connect more than one signal
>>at the same time to that pin.
>>
>>So in theory it seems you can destroy the chip by sending the wrong config data.
>>That is very bad chip design IMO.
>>
>>Maybe there is some protection, but then the datasheet is wrong.
>>So I added a software abort in case the wrong bits are set.
>
>There have been some chips, like FPGAs, that could literally be fried
>by software mis-configuration, but that's very rare. If the mux is
>mis-programmed, it's unlikely that any damage would be done.


Yes, the FPGA oscillating over a few gates really heats it up, causes hot spots!
Been there, done that, but it did survive.

In the LMX2332 datasheet I do not see any power on states of the configuration registers specified either.
Better have a current limiting resistor in the supply I think...

Thread

tiny board John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-09 20:22 -0700
  Re: tiny board <698839253X6D445TD@nospam.org> - 2018-10-10 06:30 +0000
    Re: tiny board tabbypurr@gmail.com - 2018-10-10 02:39 -0700
      Re: tiny board <698839253X6D445TD@nospam.org> - 2018-10-10 14:08 +0000
        Re: tiny board tabbypurr@gmail.com - 2018-10-10 08:34 -0700
    Re: tiny board DecadentLinuxUserNumeroUno@decadence.org - 2018-10-10 09:54 +0000
    Re: tiny board John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-10 07:43 -0700
    Re: tiny board John Larkin <jjlarkin@highland_snip_technology.com> - 2018-10-10 11:12 -0700
      Re: tiny board <698839253X6D445TD@nospam.org> - 2018-10-10 19:12 +0000
        Re: tiny board John Larkin <jjlarkin@highland_snip_technology.com> - 2018-10-10 12:26 -0700
          Re: tiny board <698839253X6D445TD@nospam.org> - 2018-10-12 17:57 +0000
            Re: tiny board John Larkin <jjlarkin@highland_snip_technology.com> - 2018-10-12 12:55 -0700
              Re: tiny board <698839253X6D445TD@nospam.org> - 2018-10-13 06:59 +0000
                Re: tiny board John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-13 08:54 -0700
                Re: tiny board <698839253X6D445TD@nospam.org> - 2018-10-13 18:19 +0000
  Re: tiny board George Herold <gherold@teachspin.com> - 2018-10-10 06:40 -0700
    Re: tiny board John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-10 07:38 -0700

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