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'PLEASE - HELP ME! PIC17C4X - AGAIN'
1998\04\28@005451 by WF AUTOMACAO

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Hi,

       Did you run someone external program on PIC17C4X, where's the
executable code is into the a external RAM?

       I wrote a program into the external EPROM (address 0x0000) of
PIC17C4X that loads a .bin file from serial, and put it on external RAM.
My program verify the program on RAM is correct with success, but,
when try to execute it, fail!.
       I think that then RAM -100 -120ns that i'm using are too slow for
PIC17C4X.

       Am i correct?

       Miguel.

1998\04\28@051100 by g.daniel.invent.design

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Miguel:
Try a slower XTAL clock frequency to verify your conclusion !
regards,
Graham Daniel

WF AUTOMACAO wrote:
{Quote hidden}

1998\04\28@063512 by Andy Kunz

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>PIC17C4X that loads a .bin file from serial, and put it on external RAM.

Miguel,

I hope your program is executing from a different part of memory.  The
PIC17 chips can program themselves using the table write commands.  You
need to have the external ram at a different address during this operation
for it to work properly.

Otherwise, you may be programming the internal ROM.  Just because Vpp is 5v
doesn't mean it won't try to program - it just won't program reliably!

>        I think that then RAM -100 -120ns that i'm using are too slow for
>PIC17C4X.

Microchip recommends 100nS chips for 20MHz part.  If you look at the timing
diagrams, they are 2 clock times wide.

Andy

==================================================================
                    Andy Kunz - Montana Design
         Go fast, turn right, and keep the wet side down!
==================================================================

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