Interfacing TAOS photodiode array
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If have got an OEMBS2 and I want to interface the TAOS linear sensor
array for a bar-code reading application. The sensor consists of an
array of 64 photodiodes controlled by a shift register. You might
want to take a look at the data sheet:
http://www.image-sensor.com/pdf/taos/TSL201.pdf
In the following program I first send the pulse to integrate all the
pixels and then I try to read the shift register. In the first
reading cycle after power-up it do appears to work: when I put the
finger over the chip most of the bits are 0s, otherwise 1s. But it
just works for the first cycle and then, the debug screen only shows
64 1s. I tried lots of different codes and modes, but it never
worked.
'{$STAMP BS2}
'{$PBASIC 2.5}
'{$PORT COM1}
SI CON 0
CLK CON 1
AO CON 2
dat VAR Word(4)
PAUSE 1000
top:
HIGH SI
PULSOUT CLK,5
LOW SI
SHIFTIN AO, CLK, MSBPRE, [noparse][[/noparse]dat(1)\16, dat(2)\16, dat(3)\16, dat(4)\16]
DEBUG CLS, BIN dat(1), BIN dat(2), BIN dat(3), BIN dat(4)
PAUSE 1000
GOTO top
Any idea?
array for a bar-code reading application. The sensor consists of an
array of 64 photodiodes controlled by a shift register. You might
want to take a look at the data sheet:
http://www.image-sensor.com/pdf/taos/TSL201.pdf
In the following program I first send the pulse to integrate all the
pixels and then I try to read the shift register. In the first
reading cycle after power-up it do appears to work: when I put the
finger over the chip most of the bits are 0s, otherwise 1s. But it
just works for the first cycle and then, the debug screen only shows
64 1s. I tried lots of different codes and modes, but it never
worked.
'{$STAMP BS2}
'{$PBASIC 2.5}
'{$PORT COM1}
SI CON 0
CLK CON 1
AO CON 2
dat VAR Word(4)
PAUSE 1000
top:
HIGH SI
PULSOUT CLK,5
LOW SI
SHIFTIN AO, CLK, MSBPRE, [noparse][[/noparse]dat(1)\16, dat(2)\16, dat(3)\16, dat(4)\16]
DEBUG CLS, BIN dat(1), BIN dat(2), BIN dat(3), BIN dat(4)
PAUSE 1000
GOTO top
Any idea?
Comments
Did you try a pull down resistor at Ao? from the schematic on page 1
of the tech doc it looks like Ao is an open source output;
therefore, methinks you need a pull down resistor.
take it to the dome,
slavorkian
--- In basicstamps@yahoogroups.com, "nicsusr" <nicolas@n...> wrote:
> If have got an OEMBS2 and I want to interface the TAOS linear
sensor
> array for a bar-code reading application. The sensor consists of an
> array of 64 photodiodes controlled by a shift register. You might
> want to take a look at the data sheet:
> http://www.image-sensor.com/pdf/taos/TSL201.pdf
>
>
> In the following program I first send the pulse to integrate all
the
> pixels and then I try to read the shift register. In the first
> reading cycle after power-up it do appears to work: when I put the
> finger over the chip most of the bits are 0s, otherwise 1s. But it
> just works for the first cycle and then, the debug screen only
shows
> 64 1s. I tried lots of different codes and modes, but it never
> worked.
>
>
>
> '{$STAMP BS2}
> '{$PBASIC 2.5}
> '{$PORT COM1}
>
>
>
> SI CON 0
> CLK CON 1
> AO CON 2
> dat VAR Word(4)
>
>
>
> PAUSE 1000
>
>
>
> top:
>
>
>
> HIGH SI
> PULSOUT CLK,5
> LOW SI
>
>
>
>
> SHIFTIN AO, CLK, MSBPRE, [noparse][[/noparse]dat(1)\16, dat(2)\16, dat(3)\16, dat(4)
\16]
> DEBUG CLS, BIN dat(1), BIN dat(2), BIN dat(3), BIN dat(4)
>
>
>
>
> PAUSE 1000
> GOTO top
>
>
>
>
>
>
>
> Any idea?