Alt-BEAM Archive
Message #05306
To: beam@sgiblab.sgi.com
From: David Perry davidperry@geocities.com
Date: Sun, 18 Jul 1999 16:37:12 -0400
Subject: Re: MPNC was AUTOMATIC PNC
> holy crap! you have revolutionised the microcore!!!!!!!!!
> It will be the end of the traditional microcore and PNC as we know it!!!!
> damn, to late to implement into my caterpillerBot.
>
> One question while i'm at it, i am using 2x 74hc240 to reverse my new bot,
> but it has 4 reverse switches when i only want one. is it safe to hook
them
> all up ?
>
> David Perry
>
>
> -----Original Message-----
> From: Sean Rigter
> To: BEAM
> Date: Sunday, 18 July 1999 4:44
> Subject: MPNC was AUTOMATIC PNC
>
>
> >Hello group,
> >
> >Nudged by Bruce Robinson,
> >
> >>But, umm, tell me. How would your circuit look for a 6-Nv microcore?
> >.
> >
> >here is an short article describing an improved PNC circuit with
> >examples for 4 and 6 Nv cores. Also included is an introduction to MPIC
> >pulse injection controlled gait changes. The latter is an untested
> >experimental design and there is much detail to be worked out. Feel
> >free to build it and report back to BEAM land.
> >
> >enjoy
> >
> >wilf
> >
> >
> >
> > MPNC Nvcores - a logical solution for saturation problems
> > using the multiple pulse neutralizing circuit
> > wilf rigter - 07/99
> >
> >In a conventional microcore design the dreaded twin process saturation
> >problem is addressed with a Nu based pulse neutralizing circuit (PNC)
> >which absorbs all circulating processes and when it times out initiates
> >a single process in the microcore. Since the PNC forces one Nv output
> >active low any motor connected to that Nv would be rotating possibly
> >mangling a pair of legs in the process. This is normally avoided by
> >disabling the output drivers during the time the PNC is active.
> >
> >Despite the PNC's longevity in BEAM land, all things must change as old
> >PNC based ucore designs are superseded by a new generation of Nv core
> >designs which include a "multiple process neutralizing circuit" (MPNC).
> >Unlike the PNC base ucore circuits, this new design instantly
> >initializes the Nvcore and does not require any motor driver inhibit.
> >After power up, the MPNC constantly monitors for and neutralizes
> >multiple processes in the core. Since the MPNC does not require an Nu
> >inverter, a single 74HC14 can be used for a 6Nv core.
> >
> >The MPNC design is added to a Nvcore with simple diode logic requiring
> >only 2 diodes for a 4Nv ucore and 4 diodes for a 6Nv hexcore.
> >
> >THE 4NvMPNC
> >
> >A 4Nv microcore uses 2 diodes to snuff out core saturation by
> >neutralizing multiple (twin) processes with the anodes of the diodes
> >connected to N1 and Nv2 outputs and the cathodes to Nv3 and Nv4 bias
> >points respectively. 4NvMPNC.GIF shows the schematic for a MPNC ucore
> >complete with a 74AC240 reverser circuit. The MPNC logic is simple: with
> >two possible saturation states (NV1 AND Nv3 active or Nv2 AND Nv4
> >active), the 1Nv output is active low and this level connected through
> >the diode to the Nv3 bias point forces the Nv3 output high, neutralizing
> >the saturation process. Similarly the Nv2 output neutralizes any
> >potential saturation process in Nv4.
> >
> >THE 6NvMPNC
> >
> >A 6Nv MPNC hexcore requires 4 diodes compared to the 2 diode MPNC ucore
> >to neutralize not only twin but also triplett multiple processes. To
> >instantly start the 6Nv core with a simgle process in Nv1 the diodes are
> >connected as follows: The anodes of 3 diodes are connected to Nv1 output
> >with cathodes connected to the bias points of Nv3, Nv4 and Nv5. The
> >fourth diode anode is connected to Nv2 output and cathode to Nv6 bias
> >point. The graphic 6NvMPNC.GIF is attached showing the schematic of a
> >6Nv hexcore with MPNC.
> >
> >THE 6NvMPIC
> >
> >As an introduction to the more advanced concept of the Multiple Process
> >Injection Circuit (MPIC) for gait control, I have included 6NVMPIC, a
> >draft schematic which shows how one can inject (and regenerate) an
> >arbitary number of processes in a 6 Nvcore. The MPIC includes the same
> >function as the MPNC since it must be able to inject as well as
> >neutralize in order to control processes. It is possible to add the MPIC
> >to a conventional PNC design to initiate the gait at power up. The MPIC
> >control lines can be connected to a number of sources including DIP
> >switch, "Collission Nu", "Turning Nu" etc but also (via a simple
> >infrared or radio link) to an IBM PC printer port or onboard STAMP or
> >PIC I/O line. The example shows a single process default HexCore with 20
> >second duration Nu controlled process injection circuits.
> >
> >
>
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