the DTR signal drives the Reset signal and RTS is used for P0.14
Andreas
--- In , "J.C. Wren" <jcwren@j...> wrote: > Richard,
>
> Can you check this schematic again? On a DB-9, pin 4 is DTR and pin > 7 is RTS. These are reversed on the schematic. Is
DTR intended to
> drive P0.14 or /RST?
>
> --jc
>
> Richard wrote:
>
> > I have uploaded this version to the files area. I also uploaded a
> > picture of the required circuitry. This circuitry is already
> > implemented on the IAR Kickstart and Keil MCB2100 evaluation boards.
> > It is really handy as ISP development can be done relatively
quickly
> > and "hands-off".
> >
> > Cheers
> >
> > Richard
Can you check this schematic again? On a DB-9, pin 4 is DTR and pin
7 is RTS. These are reversed on the schematic. Is DTR intended to
drive P0.14 or /RST?
--jc
Richard wrote:
> I have uploaded this version to the files area. I
also uploaded a
> picture of the required circuitry. This circuitry is already
> implemented on the IAR Kickstart and Keil MCB2100 evaluation boards.
> It is really handy as ISP development can be done relatively quickly
> and "hands-off".
>
> Cheers
>
> Richard
Reply by Richard●February 5, 20042004-02-05
I fixed the schematic. Thanks for the heads-up.
Richard
--- In , "J.C. Wren" <jcwren@j...> wrote: > While a good idea from an engineering perspective,
remember that > RS-232 drivers are meant to survive dead shorts,
including shorting a > high line to a low line (+12 to -12). The circuit
may not function
> correctly, but it won't (shouldn't) blow the driver.
>
> --jc
>
> haack0815 wrote:
>
> > Hi Richard,
> >
> > i think the position of D3,4 is wrong.
> > What happens when DTR or RTS are '1' (negative voltage)?
> > You better place D3,4 behind the 33k resitor to protect the drivers > > of your PC.
> >
> > Andreas
> >
> > --- In , "Richard" <richas@y...> wrote:
> > > I have uploaded this version to the files area. I also uploaded a > > > picture of the required circuitry. This
circuitry is already
> > > implemented on the IAR Kickstart and Keil MCB2100 evaluation boards. > > > It is really handy as ISP development
can be done relatively quickly > > > and "hands-off".
> > >
> > > Cheers
> > >
> > > Richard
> >
> >
Reply by J.C. Wren●February 5, 20042004-02-05
While a good idea from an engineering perspective, remember that
RS-232 drivers are meant to survive dead shorts, including shorting a
high line to a low line (+12 to -12). The circuit may not function
correctly, but it won't (shouldn't) blow the driver.
--jc
haack0815 wrote:
> Hi Richard,
>
> i think the position of D3,4 is wrong.
> What happens when DTR or RTS are '1' (negative voltage)?
> You better place D3,4 behind the 33k resitor to protect the drivers
> of your PC.
>
> Andreas
>
> --- In , "Richard" <richas@y...> wrote:
> > I have uploaded this version to the files area. I also uploaded a
> > picture of the required circuitry. This circuitry is already
> > implemented on the IAR Kickstart and Keil MCB2100 evaluation boards.
> > It is really handy as ISP development can be done relatively
quickly
> > and "hands-off".
> >
> > Cheers
> >
> > Richard
Reply by Richard●February 5, 20042004-02-05
Yes, shift those right one resistor. :-)
Richard
--- In , "haack0815" <lpc_arm@s...> wrote: > Hi Richard,
>
> i think the position of D3,4 is wrong.
> What happens when DTR or RTS are '1' (negative voltage)?
> You better place D3,4 behind the 33k resitor to protect the drivers
> of your PC.
>
> Andreas
>
> --- In , "Richard" <richas@y...> wrote:
> > I have uploaded this version to the files area. I also uploaded a > > picture of the required circuitry. This
circuitry is already
> > implemented on the IAR Kickstart and Keil MCB2100 evaluation boards. > > It is really handy as ISP development can be
done relatively quickly > > and "hands-off".
> >
> > Cheers
> >
> > Richard
Reply by haack0815●February 5, 20042004-02-05
Hi Richard,
i think the position of D3,4 is wrong.
What happens when DTR or RTS are '1' (negative voltage)?
You better place D3,4 behind the 33k resitor to protect the drivers
of your PC.
Andreas
--- In , "Richard" <richas@y...> wrote: > I have uploaded this version to the files area. I
also uploaded a
> picture of the required circuitry. This circuitry is already
> implemented on the IAR Kickstart and Keil MCB2100 evaluation boards.
> It is really handy as ISP development can be done relatively quickly
> and "hands-off".
>
> Cheers
>
> Richard
Reply by Richard●February 5, 20042004-02-05
I have uploaded this version to the files area. I also uploaded a
picture of the required circuitry. This circuitry is already
implemented on the IAR Kickstart and Keil MCB2100 evaluation boards.
It is really handy as ISP development can be done relatively quickly
and "hands-off".
