Built-in Analog to Digital Converter

Thanks to Gmoon (what's your real name?) for hacking out some code for reading the internal ADC supplied on Hummer units. Visit his Hummer website here.

A little background information. First off, when the designers were making the Hummer they found that the built-in analog-digital converters which are built into the DTV chip were not reliable enough. So they added a 3rd party chip to the design. It is a clone of the SNAD01C. It is an 8-bit serial ADC and it actually has 8 input lines. However, only one of those lines is present on the hummer's PCB. The rest are covered under the epoxy, and like the DTV chip itself, are unreachable.

The chip is attached to the DTV via userport lines 0, 1, and 2. I actually severed these lines on most of my hacked hummer units so that I could have the entire user-port available. Gmoon has provided source code and a compiled program. I have graciously copied them from his website and placed them here:
ADCV11.ASM - Source code, well documented
ADCV11.PRG - Compiled ML program.

adcv11b.asm - Modified version (by me) so that it displays the number on the screen from ML.
adcv11.prg - Just type SYS 49152 to start this version.


Minimal BASIC example:
10 SYS41952
20 PRINT PEEK(251);
30 GOTO10


How the routine works

The code follows the protocol outlined in this image:

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