How to review the Neo900 schematics
The easiest way to access the Neo900 schematics is by opening
http://neo900.org/stuff/kicad/proto_v2/2016-11-20/neo900__proto_v2__by_eeshow.pdf
(or our frequently updated
development
snapshot)
with your Web browser.
Read with eeshow
Eeshow is a schematics viewer
we made to help with working on the Neo900 schematics. (But one can use it
for other projects, too.) Eeshow runs on Linux.
For reviews, an important feature is the ability to quickly open
data sheets directly from the schematics. The setup process is as
follows:
- Install eeshow:
An experimental
package is available for Debian.
Or follow the build
instructions.
- Clone the repository containing the Neo900 schematics:
git clone http://neo900.org/git/ee
cd ee/hw
make pull
- Initialize the data sheet cache:
eeshow-viewer -m
This creates a directory $HOME/.eeshow-viewer-cache
- View the schematics:
make view
On the first invocation, this will download about 100 MB of data sheets.
See the eeshow documentation
for how to navigate through the schematics and how to open data sheets.
What to look for
There are many issues that can be found in a review. The following list
are just examples for things to look for. When reviewing the schematics,
you will develop a deeper understanding of the circuit and be able to
detect problems and inconsistencies that may not be obvious at a first
glance.
- Signals that connect to pins that are not compatible with the function,
- Circuits that diverge from the reference circuits in data sheets
(such differences can be intentional, but especially minor differences
may be the product of a mistake)
- Mismatched voltage levels on inputs and outputs.
E.g., if an input is driven with a "high" voltage that is below
Vih(min).
- Incorrect supply voltages.
- etc.
Discuss your findings
If you find something that looks suspicious or if you have questions,
please use the channel
#neo900
on Freenode.