Re: Antw: RE: /XMEM
Decided do some tests with a LED hooked up to /XMEM (with a 330 ohm resistor in series) Whenever the /XMEM line gets active low the LED would ilLuminate. Once bit 7 of HMPR port was set the LED would light up with any combination with address line 15 high: I/O ports &8000+ Refresh with I Register &80+ Memory &8000 So /XMEM is just the XMEM bit nanded with A15. Just thought I share it and waste your precious brain space for yummy recipies :-) BTW Scans of schematics are still welcome ! Edwin
RE: Antw: RE: /XMEM
It's fully encoded with A15 and MREQ, from what I remember. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Wednesday, March 24, 2004 3:34 AM To: sam-users@nvg.ntnu.no Subject: Antw: RE: /XMEM Thanks for the braindump Simon But your talking about the decoded signals decoded by the interface. What i need to know is the ASICs implementation of the /XMEM signal. ie is it just a bit that can be turned on and off or if it is fully encoded with A15 & /MREQ (//RFS?) NVG is back online. and I had a look at the SAMSON SRAM PCX files. I noticed /XMEM is used together with /MREQ. I wonder if this is the same with the MGT SOFT ROM. I remember that the MGT SOFT ROM schematic was also in the technical manual. Does anyone have a scan of it ? Edwin
Re: Antw: RE: /XMEM
I've got the technical manual. If it's in there, I can do you a scan, no problem. Andy [EMAIL PROTECTED] wrote: Thanks for the braindump SimonBut your talking about the decoded signals decoded by the interface.What i need to know is the ASICs implementation of the /XMEM signal.ie is it just a bit that can be turned on and off or if it is fully encoded withA15 & /MREQ (//RFS?)NVG is back online. and I had a look at the SAMSON SRAM PCX files.I noticed /XMEM is used together with /MREQ.I wonder if this is the same with the MGT SOFT ROM.I remember that the MGT SOFT ROM schematic was alsoin the technical manual. Does anyone have a scan of it ?Edwin
Antw: RE: /XMEM
Thanks for the braindump Simon But your talking about the decoded signals decoded by the interface. What i need to know is the ASICs implementation of the /XMEM signal. ie is it just a bit that can be turned on and off or if it is fully encoded with A15 & /MREQ (//RFS?) NVG is back online. and I had a look at the SAMSON SRAM PCX files. I noticed /XMEM is used together with /MREQ. I wonder if this is the same with the MGT SOFT ROM. I remember that the MGT SOFT ROM schematic was also in the technical manual. Does anyone have a scan of it ? Edwin
RE: /XMEM
Well you did do a lot of fiddling around with it for the Ryan ;)Simon Cooke <[EMAIL PROTECTED]> wrote: IIRC, the XMEM line goes low when the external memory area is addressed(upper 32k of the memory map, with external memory turned on in HMEM).The external memory addressing is controlled by two latches at ports 128 and129 (XMEML and XMEMH), which decide which 16k page of the external memory ispaged into the section between 32768 and 49151 (XMEML), and 49152 to 65535(XMEMH).And yes, I wish I could ditch that info from my brain to make room for otherstuff - like maybe recipes for interesting kinds of jello.-Original Message-From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] OnBehalf Of Edwin BlinkSent: Tuesday, March 23, 2004 2:51 PMTo: sam-users@nvg.ntnu.noSubject: /XMEMThanks for trying. Nev,GeoffI was looking for info about the /XMEM signal as the manal is not veryinformative.Does anybody know the implementation of it? or has a schematic of the 1Megexpansion or original Soft Rom board in which this signal is also used ?Edwin
RE: /XMEM
IIRC, the XMEM line goes low when the external memory area is addressed (upper 32k of the memory map, with external memory turned on in HMEM). The external memory addressing is controlled by two latches at ports 128 and 129 (XMEML and XMEMH), which decide which 16k page of the external memory is paged into the section between 32768 and 49151 (XMEML), and 49152 to 65535 (XMEMH). And yes, I wish I could ditch that info from my brain to make room for other stuff - like maybe recipes for interesting kinds of jello. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Edwin Blink Sent: Tuesday, March 23, 2004 2:51 PM To: sam-users@nvg.ntnu.no Subject: /XMEM Thanks for trying. Nev,Geoff I was looking for info about the /XMEM signal as the manal is not very informative. Does anybody know the implementation of it? or has a schematic of the 1Meg expansion or original Soft Rom board in which this signal is also used ? Edwin
/XMEM
Thanks for trying. Nev,Geoff I was looking for info about the /XMEM signal as the manal is not very informative. Does anybody know the implementation of it? or has a schematic of the 1Meg expansion or original Soft Rom board in which this signal is also used ? Edwin
