AnalogIn test requires that analog input pins also support digital output function about ci-test-shield HOT 8 CLOSED

I think it is a fair assumption that all pins can be digital IO. This assumption is an underlying assumption made in the mbed SDK, so having a ping that cannot do GPIO would be an SDK implementation error, not a test case?

@sg- care to comment on this one?

from ci-test-shield.

My previous though was that a resistor ladder would provide the coverage needed and avoid this case where analog pins are not digital capable

from ci-test-shield.

Will consider changing to resistor ladder for next revision. But how often is it the case that a pin can do analog in but not digital out?

from ci-test-shield.

I think that most mcus these days probably do offer both analog and digital capabilities on the same pin. But there are definitely potential cases where they do not - most probably on high-precision ADCs. In my opinion, a simple circuit that isolates the feature under test (analogin, not analogin + digitalout) would be preferred.

from ci-test-shield.

I do not disagree, the problem is we're pretty far down the path to getting these produced, making any HW changes would delay the release of the CI Test Shield by 1-2 months. Is this worth it?

Also, wouldnt adding a resistor ladder across A0-5 messup the analogout test? Or are you proposing a resistor ladder across A0-3 with A4-5 being loopback?

from ci-test-shield.

As a solution I have added the 'assumptions' tests, which will check the assumptions made in the tests. In this case the TESTS/assumptions/analogin/analogin.cpp test will check that the AnalogIn pins can be used as DigitalOut pins. If not then the assumption fails, as does the entire test. Is this an acceptable solution?

from ci-test-shield.

@maclobdell are the assumptions tests an acceptable solution?

from ci-test-shield.

Marking as resolved.

from ci-test-shield.