Problem making a mag card reader/decoder

Archiver

Hi all. I just got my first two Basic Stamp kits (bought the BS2 OEM
kits and built them myself), but I'm having a heck of a time getting
this to work. I'm trying to build a decoder for a magnetic card
reader. I just need to read in the TTL logic levels when the clock
goes low, buffer them up until I have 5 bits, then output them on a
serial output. My problem is however that it looks like my card
reader is not playing nice with the IO pins. It is sending a voltage
of ~4.80, yet the status of the pin is still 0. When I take the pin
and send it to the +5v (really +4.95) for an instant, it goes to 1.
Is the basic stamp that sensitive, or am I missing something. I'm
including the code I'm using for now to test the clock.

Thanks in advance,
--Brian

'{$STAMP BS2}
'{$PBASIC 2.5}
INPUT 5
INPUT 1
p5 PIN 5 '--Clock
p1 PIN 1 '--Data
clock VAR Bit
counter VAR Byte
datain VAR Bit

clock = IN5
counter = 0
DEBUG "Ready...",CR,LF
DEBUG "clock: ",BIN IN5, CR,LF
Main:
DEBUG "clock: ",BIN IN5, CR,LF
IF (clock <> 0) THEN
counter = counter + 1
datain = ~p1
DEBUG "not = ",DEC counter,CR,LF
DEBUG HEX datain,CR,LF
ENDIF
GOTO main

Archiver

I fixed that problem...stupid coding mistake. However, it still is
not working correctly. The stamp is only picking up about 6-10 clock
pulses, but when I attach the card reader to a scope, there are lots
more...so I'm assuming the card reader is working correctly. Has
anyone done this before? I would be greatful for any help from
anyone.

Thanks,
--Brian

--- In basicstamps@yahoogroups.com, "Brian M." <bjm1287@r...> wrote:
> Hi all. I just got my first two Basic Stamp kits (bought the BS2
OEM
> kits and built them myself), but I'm having a heck of a time getting
> this to work. I'm trying to build a decoder for a magnetic card
> reader. I just need to read in the TTL logic levels when the clock
> goes low, buffer them up until I have 5 bits, then output them on a
> serial output. My problem is however that it looks like my card
> reader is not playing nice with the IO pins. It is sending a
voltage
> of ~4.80, yet the status of the pin is still 0. When I take the pin
> and send it to the +5v (really +4.95) for an instant, it goes to 1.
> Is the basic stamp that sensitive, or am I missing something. I'm
> including the code I'm using for now to test the clock.
>
> Thanks in advance,
> --Brian
>
> '{$STAMP BS2}
> '{$PBASIC 2.5}
> INPUT 5
> INPUT 1
> p5 PIN 5 '--Clock
> p1 PIN 1 '--Data
> clock VAR Bit
> counter VAR Byte
> datain VAR Bit
>
> clock = IN5
> counter = 0
> DEBUG "Ready...",CR,LF
> DEBUG "clock: ",BIN IN5, CR,LF
> Main:
> DEBUG "clock: ",BIN IN5, CR,LF
> IF (clock <> 0) THEN
> counter = counter + 1
> datain = ~p1
> DEBUG "not = ",DEC counter,CR,LF
> DEBUG HEX datain,CR,LF
> ENDIF
> GOTO main