Lpc2000

Eugene,

A soft reset of the CPU is easy enough to arrange. However, what's 
less easy to arrange is that each and every peripheral is reset to a 
known, correct state with 100% reliability. Although I haven't seen 
it on the LPC2000 series, on other MCUs I've seen peripherals get 
latched into usless states by attempting a soft reset of the system 
(usually invoked when something bad has happened).

In other words, your idea of using the watchdog to do the actual 
reset is sound: you're ensured of getting a system in a known 
initial state.

How about writing a "magic" value to somewhere in RAM before you do 
a planned watchdog reset, and then checking it before you zero 
out/load initialised RAM as part of normal startup procedure? I've 
seen this technique used in the past. Obviously you'd need to check 
that the magic value is zeroed out as soon as it's read.

Brendan

--- In lpc2000@yahoogroups.com, "y3peng" <eugene.peng@...> wrote:
>
> Hi there,
> The project I am working on requires a software reset after a 
firmware
> upgrade. 
> 
> One possible solution is to setup a really short watchdog timer.
> However, the firmware design already has a watchdog timer with it, 
so
> it would be harder to distinguish between a real watchdog reset and
> our intentional reset.
> 
> Is there any other ways to cause a software reset in LPC2148?
> 
> The problem may also be with our bootloader design because the
> firmware seems to hung when it is started right after being 
upgraded.
> Though it has no issues after a reset.
> 
> Thank you for all your help!
> 
> Eugene
>