Lpc2000

Hello misstero,

Wednesday, April 26, 2006, 8:42:10 PM, you wrote:

m> Dear All,

m> I have design which is connected modem signals to UART1 (Full UART) of
m> LPC2xxxx but I found serious problem with DCD signal.

m> DCD signal of UART1 is alternate function on P0.14 which is LPC2xxx
m> bootloader determine during reset to go into Bootloader mode if it low.

m> Our problem occur when modem connected that DCD is active (Active Low
m> same as bootloader mode request) and LPC2xxx is reseted which may
m> cause by unstable power or external reset via RESET pin by
m> supervisory. This made LPC2xxx  go into bootloader mode forever cannot
m> return back to our application code even modem's DCD inactive later.
m> Only power cycle both LPC2xxx and modem to restart it to application
m> code. This case unaccetable when devices are installed in unman location.

m> I have an idea to solve this problem but it need help from Philips by
m> add time-out in Bootloader mode if it does not have any activity for
m> short period of time (etc. 3s) it should be retry to execute
m> application code repeatly so I'd like to ask Philips is it possible?

m> Anyone have other ideas to solve this problem? Please share with me. I
m> prefer to solve by software first if it possible.

m> Thanks,
m> Suriyan.

In similar situation, I use one pin for powering up modem over MOSFET
which is always off after any kind of reset. MOSFET is controlled by
pin, and after reset pin is input, and MOSFET is off. after some
init, I turn ON modem and it works fine!

-- 
Best regards,
 Branko