--- In lpc2000@lpc2..., "Sagaert Johan" <sagaert.j@...>
wrote:
> I am a bit confused : some evaluation boards use a
pull-up
(olimex) some
> other (mcb2103 ) use a pull-down resistor on the
RTCK pin.
>
> Whats the correct one ?
Depends on what you want to do with the board and how your debugger
handles RTCK during pulling reset:
RTCK is P1.26, which according to UM10120 (this is for Lpc213x)
chapter 7.4.3 p.78 determines the usage of P1.26..P1.31: either JTAG
pins or GPIO. A pulldown makes these guys debugger pins, while a
pullup makes them (initially) GPIOs.
Now if your debug cable overrides the pullup while operating the
reset, all is well. If it doesn't you have to put a a pulldown
otherwise you cannot do JTAG debugging. So a pulldown is a safe bet,
while a pullup is advantageous, if you don't want to waste power
(internal pullup and external pulldown) in deep sleep mode.
Gunter
Hi
I am a bit confused : some evaluation boards use a pull-up (olimex) some
other (mcb2103 ) use a pull-down resistor on the RTCK pin.
Whats the correct one ?
Johan