opulo-inc / feeder

Source for LumenPnP Feeders

GNU General Public License v3.0

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NRST/RESET line doesn't require a pull-up resistor #25

Closed stuartpittaway closed 1 year ago

stuartpittaway commented 1 year ago

Version Number

What is the latest known version number where this issue is present?

Bugfix or Enhancement

potential enhancement

Description

Resistor R4 (10K) is a pull up on the RESET line - this doesn't appear to be required according to the datasheet.

Page 69 of datasheet - NRST pin characteristics

The NRST pin input driver uses the CMOS technology. It is connected to a permanent pullup resistor, RPU

Suggested Solution

Remove R4

30350n commented 1 year ago

For reference, there was already some discussion on this topic in #16.

sphawes commented 1 year ago

Thanks for the issue @stuartpittaway! We originally followed the datasheet and didn't have that resistor, but we found that it was too weak. In some feeders, when the peel motor would power on it would lightly couple to the reset trace and cause a reset. Adding a stronger external pullup fixed the issue!