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LPC210x Flash Utility with RTS/DTR Control

Started by Richard February 5, 2004
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




An Engineer's Guide to the LPC2100 Series

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





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




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





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
> >
> >




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



Hi jc,

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