Our original idea was a Super Mario Brothers type game, however, we quickly realized that we would not be able to accomplish this because of the speed and memory limitations of the AtMega32 and the amount of time such a game would take to create. We switched to a Tetris type game because of its low resolution requirements, simplicity of play, and its extraordinary source of gaming fun. If we had to do it again, we would have probably prototyped the board, because we ran into some hardware problems that were complicated by soldering and desoldering. We also would have studied up on TV signals ahead of time instead of learning as we went, especially since we used a PCB. We could have made a more complicated game with a chip with more speed and memory.
NTCS standards are very strict and we did our very best to follow them. We managed to keep our signal from interfering with the vertical sync so that the image is stable on the screen. Also, we eliminated the extra interrupt that was fighting with the external horizontal sync causing a nasty distortion. This gives a fairly clear, bright signal; however, the image does experience a slight "wiggle". We were unable to nail down the exact cause of this, however we believe it to be caused by inherit timing problems. The speed of the AtMega32 coupled with inaccuracies in the crystal oscillators prevented the signal from being perfectly synced. So, itís not our fault, we swear!
We drew heavily from the Psychedelic Snake project from the Spring of 2002 that used an AtMega16. Although their schematic was incomplete, we used many of there hardware ideas and got idea for the Elm Sync Generator and Analog Devices RGB to NTSC converter from them. We also consulted old projects and various websites about the design of the Sega Genesis controller. The Tetris game is also a copyrighted program, hence the name TET. Despite the troubled legal history of Tetris, we feel confident the kind people at The Tetris Company LLC wonít feel threatened.
To find out all about Tetrisís checkered past from an independent source click here.
This project led us on shaky ethical ground on a regular basis.
(1)We are prepared to accept responsibility for the evitable seizures caused by the annoying "wiggle" on the screen, the psychological breakdowns people will have when they realize they can never beat the TET Box, and any death caused the considerable choking hazard the TET box presents.
(2)We strived to avoid conflicts of interest; however, we will take this opportunity to disclose that our desire for a good grade in this class conflicted with our desire to smash the lab into tiny pieces on several occasions.
(3)We were honest when we submitted our project proposal, but we now realize it was completely unrealistic, and apologize. We attempted to remedy this by amending the project to TET, a far more plausible idea.
(4)Once, while in lab, we were offered candy in exchange for our bench. We realized we could not accept the bribe, so we stole the candy instead (not really).
(5)Through the course of this project our understanding of video signals, syncing, and the AtMega32 were greatly improved and we will always strive to continue this improvement.
(6)The object of this lab was to improve our technical competence, which was, arguably, achieved, theoretically contributing to qualifying us to take on position in a commercial setting.
(7)Our group dealt with much internal constructive criticism which facilitated the elimination of many bugs that could never have been found by the person that created them. We also sought the help of Professor Land and the TAs, without which, this project could never have been completed. We also gave credit to the many groups of people we borrowed ideas from.
(8)Treating all people fairly, especially when they include a
big, dumb white kid
a small, angry brown man, can be very difficult, but
we feel we achieved
as well as anyone could.
(9)We always followed safety precautions in lab and while soldering. Luckily, only our own reputations were at stake, and we feel we protected them amply.
(10)In the lab, we experienced a great deal of cooperation with other groups. We had to share the color TV on several occasions, and an amicable agreement was always reach. Groups were always generous sharing equipment, and we strove to do the same. (Yeah, not much shaky ethical ground, but it kept you reading didnít it!?)
Sega Genesis Controller Pinout Website
Psychedelic Snake Website