FreeEMS Issues - Firmware
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0000184FirmwareAnalogue Inputspublic2011-06-18 17:192013-05-27 01:13
Fred 
Fred 
normalminorN/A
assignedopen 
 
Future 
Improvement
medium
0000184: Measure different kinds of ADC inputs in different ways
Copy/paste from my diary thread:


OK, there are some refinements to the way ADC pins are measured required. Some of this came from logs and some from talking to friends about this stuff.

CHT should be main loop or RTI sampled and slow averaged
BRV should be decoder sampled and quickly averaged.
IAT should be fast sampled, minimal averaging
TPS should be fast sampled, minimal averaging
MAP should be decoder sampled and not averaged, or averaged VERY little, bad map values are the result of improper reading timing..
Multi MAP should be decoder sampled and minimum taken from N cylinder readings and not averaged, or averaged VERY little, bad map values are the result of improper reading timing..
EGO can be measured either from decoder (for a consistent reading) or fast from the main loop to watch cylinder to cylinder variation, both can be done and stored differently.

To support this, each style should be configurable and when a reading is done from a particular code segment, only the things that should be being read get read. IE, some from one source, some from another. Fire calculations based on timed readings as they are most critical and volatile.
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Notes
(0001205)
Fred   
2012-02-16 01:26   
Actually, it's really important that BRV is sampled in a timed way too. Reason being that starter current draw is engine compression dependent, so starting will never be consistent unless this is timed.
(0002660)
Fred   
2013-05-27 01:13   
Along with new timed readings, we should keep reading certain things often so as to be able to observe behaviour, and store this in a different var, eg:

InstantaneousMAP vs. MAP