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project:atari_asteroids_autoplay [2013/03/13 20:49] – [Resources Used] smark | project:atari_asteroids_autoplay [2013/03/17 05:08] – [Resources Used] smark | ||
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Basically I believe I need to intercept the outputs of XVLD, YVLD, and BVLD. This is where all of the digital signals are condensed into the X, Y, and On/Off digital stream. From here it goes to the DACs which convert it to output to the Electrohome. I hooked an oscilloscope up to one of the leads of one of the LS134(?) chips which I think is XVLD or YVLD. Using the test pattern (which keeps the picture static) I was able to get a good look at the signal going through there. It looks like how I think a digital signal would look on an analog oscillocope... Lines at 0 and Lines at positive whatever voltage with no connections in between. Almost like _-_-_-_-_ or something. | Basically I believe I need to intercept the outputs of XVLD, YVLD, and BVLD. This is where all of the digital signals are condensed into the X, Y, and On/Off digital stream. From here it goes to the DACs which convert it to output to the Electrohome. I hooked an oscilloscope up to one of the leads of one of the LS134(?) chips which I think is XVLD or YVLD. Using the test pattern (which keeps the picture static) I was able to get a good look at the signal going through there. It looks like how I think a digital signal would look on an analog oscillocope... Lines at 0 and Lines at positive whatever voltage with no connections in between. Almost like _-_-_-_-_ or something. | ||
+ | ==== 3/16/2013 @ 9:07pm ==== | ||
+ | So I haven' | ||
+ | \\ | ||
+ | I'm currently going around and around unable to decide where the best place is to intercept the data. I've found out where I can intercept it but it takes 8+ leads to get anything valuable out of it. XVLD/YVLD turned out to be a dead end as all they do are tell whether or not there is a valid value there. I'm torn in a few different directions...\\ | ||
+ | \\ | ||
+ | Get the outputs from DACX1-10* / DACY1-10* / BLVD. The X/Y ends up being 10 bit values which are fed to the actual DACs (B11/D11). I hooked the logic analyzer up to B11 pins 13 thru 6 (DACY10-3*) where Pin 13 (DACY10*) is the most significant bit (512). It can be visualized as follows: | ||
+ | |||
+ | |||
+ | ^ DACY#* | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | | ||
+ | ^ B11 Pin | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | | ||
+ | ^ Logic Channel | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | | | | ||
+ | ^ Sample Value | 1 | 0 | 1 | 0 | 1 | 1 | 0 | 1 | 0 | 0 | | ||
+ | ^ Digit Weight | 512 | 256 | 128 | 64 | 32 | 16 | 8 | 4 | 2 | 1 | | ||
+ | ^ Value | 512 | 0 | 128 | 0 | 64 | 32 | 0 | 16 | 0 | 0 | | ||
+ | ^ Total | 692 |||||||||| | ||
+ | |||
+ | Now whats important to note is that the DAC does not have an internal register so it doesn' | ||
+ | \\ | ||
+ | Anyway, I hooked the logic analyzer up to B11 Pins 13 thru 6, which leaves off pins 5 and 4, which means you lose the last two bits of accuracy. I'm not sure if it is important at this point or not. That means the last two bits are always considered 0. The Saleae Logic software is pretty cool. You end up getting data that looks like this:\\ | ||
+ | \\ | ||
+ | {{: | ||
+ | \\ | ||
+ | Well thats interesting but not really visually useful is it? If you take a vertical slice at any point in that output and assign each channel a 0 or 1 you will get the binary representation just like above. I've compiled the output for each slice (all 336,000 of them) and uploaded them here: {{: | ||
+ | \\ | ||
+ | Now that I have 336,000 height values (Y-Axis 0-1023) I was able to compile this charge with gnuplot:\\ | ||
+ | \\ | ||
+ | {{: | ||
+ | \\ | ||
+ | Well HMM that looks a little bit like the horizontal output for the test pattern! Don't quite see it? Heres a labeled version:\\ | ||
+ | \\ | ||
+ | {{: | ||
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