Lpc2000

Yup.  Since we weren't using i2c we didn't read the part that said
they're open-drain outputs.  10K pull-ups did the trick...

-----Original Message-----
From: microbit [mailto:microbit@...] 
Sent: Wednesday, July 21, 2004 2:41 PM
To: lpc2000@yahoogroups.com
Subject: Re: [lpc2000] Strange behavior on P0.02/P0.03


Have you pulled those pins ?
Off-the-cuff from memory they're the I2C pins, and open drain.
>From your sequence xample seems like you have moments where
the pull up fails, depending on the sequence

-- Kris

----- Original Message -----
From: "Curt Powell" <curt.powell@...>
To: <lpc2000@yahoogroups.com>
Sent: Thursday, July 22, 2004 7:17 AM
Subject: [lpc2000] Strange behavior on P0.02/P0.03


> We're seeing some strange pin behavior between an lpc2106 (on an
Olimex
> H2106 board) and a USB FIFO (DLPUSB245M).  I'm wondering if anyone has
> any ideas.  When running a simple loopback test sending data from lpc
to
> FIFO, bits 2 and 3 (on P0.02 and P0.03) do not get set to 1 but on the
> next byte sent they do (if they would be 1 on that byte).
>
> Example:  Sending a sequence of 16 bytes (values 0x00-0x0f) whenever
bit
> 2 or 3 transitions from 0 to 1 (i.e. on 0x4, 0x8, 0xc) it is 0 but on
> the next byte sent it is 1.  There is no issue with a 0 -> 1
transition.
>
>         hex     bin    actual
> Sending 0x00 00000000 00000000
> Sending 0x01 00000001 00000001
> Sending 0x02 00000010 00000010
> Sending 0x03 00000011 00000011
> Sending 0x04 00000100 00000000 <- bit 2 is 0, should be 1
> Sending 0x05 00000101 00000101 <- bit 2 is 1 this time
> Sending 0x06 00000110 00000110
> Sending 0x07 00000111 00000111
> Sending 0x08 00001000 00000000 <- bit 3 is 0, should be 1
> Sending 0x09 00001001 00001001 <- bit 3 is 1 this time
> Sending 0x0a 00001010 00001010
> Sending 0x0b 00001011 00001011
> Sending 0x0c 00001100 00001000 <- bit 2 is 0, should be 1
> Sending 0x0d 00001101 00001101 <- bit 2 is 1 this time
> Sending 0x0e 00001110 00001110
> Sending 0x0f 00001111 00001111
>
> This doesn't happen on any of the other 6 data pins.  We were thinking
> it might have something to do with the alternate functions on
> P0.02/P0.03 (I2C or timer 0) but we are not using those functions and
in
> fact are explicitly setting P0.02/P0.03 to GPIO at the beginning of
the
> program.
>
> Any ideas?
>
> TIA,
>
> Curt
>
>
>
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