can not pull the pin stage from low to high when connect 2 ARM together?

[hg-chen]

Posted on April 04, 2007 at 09:05

can not pull the pin stage from low to high when connect 2 ARM together?

[hg-chen]

Posted on April 04, 2007 at 08:30

1, connect 2 pins of 2 ARM together,

both pins configured as open drain,

with external pull high resistors to 3.3V

2, initila at high state, then pull low by instruction

but can not pull high anymore!

any idea ?

[kleshov]

Posted on April 04, 2007 at 09:05

If the line stays low, then something is pulling it low. It can be either of the two ARMs. Double-check everything.