Amiga.org

Amiga computer related discussion => Amiga Software Issues and Discussion => Topic started by: Hodgkinson on September 12, 2007, 12:24:04 PM

Title: RAM On RTC chips ... Just out of intrest ...
Post by: Hodgkinson on September 12, 2007, 12:24:04 PM
Im wondering wether anyone has ever tried to make the 26x4 bits of internal battery backed RAM in the RP5C01 RTC IC (As used in A4000's and can be used in RTC's on the A1200) accessable by the system?

Perhaps the RAM wont be of much use as general system RAM, but im wondering if anyone has ever used this to store information between cold reboots on, say, floppy only systems where disks are write-protected?

Just thought this might be of intrest to someone.

Hodgkinson.
Title: Re: RAM On RTC chips ... Just out of intrest ...
Post by: hardlink on September 13, 2007, 09:11:30 PM
Very good question.

I have an SGI Indy, and they cleverly/foolishly use the RTC ram for the unique system ID, which just happens to be the ethernet MAC address. There are ways to manually write to it, so you could counterfeit any possible MAC address and really confuse the RIAA trackers :)

If the A4K can read from there, and set the clock, I imagine there is a way to write.
Title: Re: RAM On RTC chips ... Just out of intrest ...
Post by: Piru on September 13, 2007, 09:13:46 PM
Consult battmem.doc

IIRC some bigbox amigas store SCSI related settings to battmem.
Title: Re: RAM On RTC chips ... Just out of intrest ...
Post by: BinoX on September 13, 2007, 10:30:24 PM
Really?

I didn't know that... as far as I remember the A3000 has some special NVRAM to store SCSI settings... Of course I'm by no means an expert as I only got an A3000 a few days ago, but that was my understanding of how it worked..

If I'm wrong, feel free to correct me... :)
Title: Re: RAM On RTC chips ... Just out of intrest ...
Post by: Hodgkinson on September 14, 2007, 04:10:41 PM
Quote

Consult battmem.doc


Where might I be able to find this document, Piru? I'd be interested to have a read...

Thanks for the replies (I thought something might have made use of the memory...)

Hodgkinson.
Title: Re: RAM On RTC chips ... Just out of intrest ...
Post by: hardlink on September 14, 2007, 04:14:29 PM
http://cataclysm.cx/random/amiga/reference/Includes_and_Autodocs_2._guide/node05B8.html