[Gmecm] CTS and MAT lookup differences

[Robin Handley]

I've now compared the Sunbird ALDL MAT raw values with ones computed from
the input resistances, (computed ones were based on the assumption of a 1k
pull-up resistor - observing that a quantity in the PROMgrammer export is
called 'MAT1K'. The match was very good. So I now believe that the ALDL MAT
values _are_ raw A/D values.

This is frustrating though as, in order to get my ALDL monitoring/logging
program to show MAT in deg C, I would have to insert a lookup table in its
code, equivalent to the one in the Sunbird code. This would be the first
occurance of this, so I'm a bit suspicious that I've got things wrong. Can
anybody comment?

Are the A/D->deg C lookup array values in the Sunbird/$58 code scaled using
the usual ARG = (deg C - 40) * (4/3) ?

I used this formula in reverse to calculate deg C from the Sunbird/$58 MAT
lookup array values, and referenced these to calculated resistance values,
based on A/D steps of 16 and a 1k pull-up resistor. I then compared these to
the values at: http://www.diy-efi.org/gmecm/component_info/sensors.html. The
result was not a good match. Does this mean the A/D->deg C formula is wrong,
or the assumption of uniform A/D steps of 16 down the MAT lookup table?

Robin