Lpc2000

---- Original Message ----
From: "nknight62" <justlooking@...>
To: <lpc2000@yahoogroups.com>
Sent: Monday, March 06, 2006 6:44 AM
Subject: [lpc2000] LPC2138 GPIO Pull Downs ?

> We have an application where we use the GPIO I/O pins on Port 1 of
> LPC2138 to an LCV244 buffer/driver.  We found that randomly, some pins
> on the buffer driver were high or low at power-up with no program
> loaded to control the pins.  We added 32k pull downs between the 2138
> and the buffer/driver inputs to pull the lines low because the GPIO
> lines are floating inputs before program changes them into outputs.
> However, we are still randomly seeing some outputs on buffer/driver
> high and some low on power up.  We measured between 0.4 and 1.2 volts
> on those lines. Why are 32k pull downs not working for us ?

Remember that all P1.x pins have internal pull-ups of 60-300 kohm.

Karl Olsen