long@sask.UUCP (Warren Long) (03/10/86)
I am the proud new owner of a 512k board for my Atari 800. I must confess that about the only way to use this memory is as a Ramdisk, and I do have the program to do this. The problem?? If/When the thing locks up on me and will not respond to System-Reset, the only thing I can do is to reboot, and lose everything. I would like one more avenue to try, that of the wiring in a button to a 'hard' reset, that is, reset the microprocessor. Once upon a time there were articles on how to do it. (a wire, a switch, and a pull-up/pull-down resistor) Anybody remember how to do it?? Part 2: Will this solve my problem, or will a hard reset to the microprocessor reboot the whole machine anyways?? Thanks, Warren Long University of Saskatchewan Canada
DYOUNG@USC-ISID.ARPA (C. David Young) (03/14/86)
If you will give me your mail address I will send you a sheet describing the coldstart mod. However, it will not do you much good unless you have an 8K OMNIMON in the system to take control after resetting the CPU. Also, I have not had much luck in preserving the contents of the ramdisk when the CPU locks up. I think the RAM must lose the refresh when the CPU locks up. David Young -------
ekijak@ARDC.ARPA ("Edmund S. Kijak", POINT) (03/14/86)
At one time, I was thinking about adding a hardware reset to the 400/800 also., and for the same reason. Seems to me that one of the 6502 cpu chip pins is a reset pin, and all you'd have to do is ground that pin momentarily to reset everything. Don't know if the op sys would go and clear memory as a result of this though.
jhs@MITRE-BEDFORD.ARPA (03/14/86)
FYI - If the 8K OMNIMON is anything like OMNIMONXL, and you are as serious about your 800 as buying a 512K upgrade suggests, you certainly shouldn't waste any time in ordering it. (Though not on the ARPANET, of course!) David's phone number, if you want information on OMNIMON, is (214) 235-2146 and his address is: CDY Consulting 421 Hanbee Richardson, TX 75080. -John Sangster jhs @ mitre-bedford.arpa NOTE: I have no financial interest in CDY Consulting; I am just a satisfied customer, having bought OMNIMONXL, the 80-column display upgrade OMNIVIEW, and the 256KXL 256-K ram upgrade for my 800XL.
DYOUNG@USC-ISID.ARPA (C. David Young) (03/15/86)
The 400/800 OS will always do a coldstart if you reset the CPU. This is done by adding a 47 ohm resistor in series with a momentary switch between the two pads near R156 on the 800 or R183 on the 400. To do the coldstart you close the coldstart switch and then press RESET. This will cause the CPU to do what it normally does on powerup, including clearing all of system RAM. However, the CPU does not clear the extra RAM which may be present (i.e., anything beyond the 64K that it knows about. This is a great advantage if you have a ramdisk since this allows you to reboot the system without losing its contents. Also it is better for your computer than cycling power. David Young -------