From: Olaniyi B. <zu...@em...> - 2003-03-12 15:34:17
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>What version of the 8051 want you to use ? I ma using the ATMEL TS87C52X2 which has an instruction cycle of 6 clock cycles. >For a generic 8051 >!PSEN goes low to fetch a Instuction. >!RD goes low to fetch xram via movx. >!WR goes down to write xram via movx. >ALE triggers the latching of the high 8 addressbits transmitted on >P0. >You need to "or" RD and PSEN to execute Programms in Xram. This is possible but I believe it is also possible to connect the /PSEN pin to the external program memory (FLASH in my case) and the /RD pin to the Data memory (SRAM in my case). Is this correct or am I mistaking? >its better to use the 138 only for decodeing the Address to !CS >Then !RDor!PSEN can drive the !OE and !WR can drive RD/!WR from the >Sram. Basically, I have connected the 138 as the chip select for my LCD and my Ethernet Card. also I use the combination of NAND and NOR gates (which only go active when the higher 10 address line are low) and the /PSEN pin to select the 138 ( connect them to the selector lines (G1 and C)). and with Addressline 4 and 5 I Chip select the Devices and use the remaining addresslines to address the peripheral devices. Does anyone have any idea as to if there are anything I am missing out. thanks Charles. P.S. www.8082.com needs a user and password. -- _______________________________________________ Sign-up for your own FREE Personalized E-mail at Mail.com http://www.mail.com/?sr=signup |
From: Gernot F. <ger...@ne...> - 2003-03-12 18:13:47
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On Wed, 12 Mar 2003, you wrote: > This is possible but I believe it is also possible to connect the /PSEN >pin to the external program memory (FLASH in my case) and the /RD pin to the >Data memory (SRAM in my case). Is this correct or am I mistaking? This is correct, but you cant execute programms in the sram. >Basically, I have connected the 138 as the chip select for my LCD and my >Ethernet Card. also I use the combination of NAND and NOR gates (which only go >active when the higher 10 address line are low) and the /PSEN pin to select the >138 ( connect them to the selector lines (G1 and C)). and with Addressline 4 I dont see the sense of the PSEN line at the addressdecoder(138). You create only a mass of noise on the selectlines. Its not necessary to lock PSEN to RD and WR. Psen is active for every opcode fetched from external Flash and never overlap or come near RD or WR. -- MFG Gernot |
From: Peter B. <alt...@go...> - 2003-03-13 09:23:40
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> You just have to wire the chips correctly.... Yes, look at this: http://www1.uni-bremen.de/~g16i/gifs/sp485.gif Peter ########################################### Ezt a levelet az F-Secure Anti-Virus for Internet Mail ellenõrizte. Miskolci Egyetem Számítóközpont |
From: Rod B. <ro...@bo...> - 2003-03-13 17:51:47
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You are missing the address decoder latch on the low order address bytes. This will never work if teh processor is a bog standard 8051. Regards, Rod On Thu, 13 Mar 2003 10:13:02 +0100 Peter Bozzay <alt...@go...> wrote: > > You just have to wire the chips correctly.... > Yes, look at this: > http://www1.uni-bremen.de/~g16i/gifs/sp485.gif > > Peter > > ########################################### > Ezt a levelet az F-Secure Anti-Virus for Internet Mail ellen_rizte. > Miskolci Egyetem Sz_m_t_k_zpont > > > ------------------------------------------------------- > This SF.net email is sponsored by:Crypto Challenge is now open! > Get cracking and register here for some mind boggling fun and > the chance of winning an Apple iPod: > http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0031en > _______________________________________________ > Sdcc-user mailing list > Sdc...@li... > https://lists.sourceforge.net/lists/listinfo/sdcc-user > |
From: Jesus Calvino-F. <Je...@ec...> - 2003-03-13 18:45:17
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The latch is a 74573 at coordinate B6. At 06:51 AM 3/14/03 +1300, you wrote: >You are missing the address decoder latch on the low order address >bytes. This will never work if teh processor is a bog standard 8051. > >Regards, >Rod > > >On Thu, 13 Mar 2003 10:13:02 +0100 >Peter Bozzay <alt...@go...> wrote: > > > > You just have to wire the chips correctly.... > > Yes, look at this: > > http://www1.uni-bremen.de/~g16i/gifs/sp485.gif > > > > Peter > > > > ########################################### > > Ezt a levelet az F-Secure Anti-Virus for Internet Mail ellen_rizte. > > Miskolci Egyetem Sz_m_t_k_zpont > > > > > > ------------------------------------------------------- > > This SF.net email is sponsored by:Crypto Challenge is now open! > > Get cracking and register here for some mind boggling fun and > > the chance of winning an Apple iPod: > > http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0031en > > _______________________________________________ > > Sdcc-user mailing list > > Sdc...@li... > > https://lists.sourceforge.net/lists/listinfo/sdcc-user > > > > >------------------------------------------------------- >This SF.net email is sponsored by:Crypto Challenge is now open! >Get cracking and register here for some mind boggling fun and >the chance of winning an Apple iPod: >http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0031en >_______________________________________________ >Sdcc-user mailing list >Sdc...@li... >https://lists.sourceforge.net/lists/listinfo/sdcc-user |
From: Rod B. <ro...@bo...> - 2003-03-14 02:18:40
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It not connected to the correct address and data lines. It looks like it is connected as a buffer of A8 to A15 what about A0 to A7 and D0 to D7? This latch is in teh wrong place and not connected correctly. A good idea but you need to look in the net for more generic 8051 expanded memory model digrams. This is my two cents worth I'm happy to be proven wrong but I do not beleive this will work in is current setup. Regards, Rod On Thu, 13 Mar 2003 10:44:57 -0800 Jesus Calvino-Fraga <Je...@ec...> wrote: > The latch is a 74573 at coordinate B6. > > At 06:51 AM 3/14/03 +1300, you wrote: > >You are missing the address decoder latch on the low order address > >bytes. This will never work if teh processor is a bog standard 8051. > > > >Regards, > >Rod > > > > > >On Thu, 13 Mar 2003 10:13:02 +0100 > >Peter Bozzay <alt...@go...> wrote: > > > > > > You just have to wire the chips correctly.... > > > Yes, look at this: > > > http://www1.uni-bremen.de/~g16i/gifs/sp485.gif > > > > > > Peter > > > > > > ########################################### > > > Ezt a levelet az F-Secure Anti-Virus for Internet Mail ellen_rizte. > > > Miskolci Egyetem Sz_m_t_k_zpont > > > > > > > > > ------------------------------------------------------- > > > This SF.net email is sponsored by:Crypto Challenge is now open! > > > Get cracking and register here for some mind boggling fun and > > > the chance of winning an Apple iPod: > > > http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0031en > > > _______________________________________________ > > > Sdcc-user mailing list > > > Sdc...@li... > > > https://lists.sourceforge.net/lists/listinfo/sdcc-user > > > > > > > > >------------------------------------------------------- > >This SF.net email is sponsored by:Crypto Challenge is now open! > >Get cracking and register here for some mind boggling fun and > >the chance of winning an Apple iPod: > >http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0031en > >_______________________________________________ > >Sdcc-user mailing list > >Sdc...@li... > >https://lists.sourceforge.net/lists/listinfo/sdcc-user > > > > > ------------------------------------------------------- > This SF.net email is sponsored by:Crypto Challenge is now open! > Get cracking and register here for some mind boggling fun and > the chance of winning an Apple iPod: > http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0031en > _______________________________________________ > Sdcc-user mailing list > Sdc...@li... > https://lists.sourceforge.net/lists/listinfo/sdcc-user > |
From: Jesus Calvino-F. <Je...@ec...> - 2003-03-14 03:17:25
|
Hi Rod, The 74573 is connected correctly. Pins 2 to 9 go to the Address/Data bus (AD0 to AD7) of the 80535 (pins 52 to 59). Pin 11, the latch enable goes to pin 50 of the 80535 (ALE). Pin 11, the output enable, is grounded. Finally pins 12 to 19 go to the address bus (A00 to A15) that carry them to the 27256 and 62256. Also, do you think a design from 1995 (look at the title box) would still be around if it were incorrect? Best regards, Jesus At 03:18 PM 3/14/2003 +1300, Rod Boyce wrote: >It not connected to the correct address and data lines. It looks like it >is connected as a buffer of A8 to A15 what about A0 to A7 and D0 to D7? > >This latch is in teh wrong place and not connected correctly. A good idea >but you need to look in the net for more generic 8051 expanded memory >model digrams. > >This is my two cents worth I'm happy to be proven wrong but I do not >beleive this will work in is current setup. > >Regards, >Rod > >On Thu, 13 Mar 2003 10:44:57 -0800 >Jesus Calvino-Fraga <Je...@ec...> wrote: > > > The latch is a 74573 at coordinate B6. > > > > At 06:51 AM 3/14/03 +1300, you wrote: > > >You are missing the address decoder latch on the low order address > > >bytes. This will never work if teh processor is a bog standard 8051. > > > > > >Regards, > > >Rod > > > > > > > > >On Thu, 13 Mar 2003 10:13:02 +0100 > > >Peter Bozzay <alt...@go...> wrote: > > > > > > > > You just have to wire the chips correctly.... > > > > Yes, look at this: > > > > http://www1.uni-bremen.de/~g16i/gifs/sp485.gif > > > > > > > > Peter > > > > > > > > ########################################### > > > > Ezt a levelet az F-Secure Anti-Virus for Internet Mail ellen_rizte. > > > > Miskolci Egyetem Sz_m_t_k_zpont > > > > > > > > > > > > ------------------------------------------------------- > > > > This SF.net email is sponsored by:Crypto Challenge is now open! > > > > Get cracking and register here for some mind boggling fun and > > > > the chance of winning an Apple iPod: > > > > http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0031en > > > > _______________________________________________ > > > > Sdcc-user mailing list > > > > Sdc...@li... > > > > https://lists.sourceforge.net/lists/listinfo/sdcc-user > > > > > > > > > > > > >------------------------------------------------------- > > >This SF.net email is sponsored by:Crypto Challenge is now open! > > >Get cracking and register here for some mind boggling fun and > > >the chance of winning an Apple iPod: > > >http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0031en > > >_______________________________________________ > > >Sdcc-user mailing list > > >Sdc...@li... > > >https://lists.sourceforge.net/lists/listinfo/sdcc-user > > > > > > > > > > ------------------------------------------------------- > > This SF.net email is sponsored by:Crypto Challenge is now open! > > Get cracking and register here for some mind boggling fun and > > the chance of winning an Apple iPod: > > http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0031en > > _______________________________________________ > > Sdcc-user mailing list > > Sdc...@li... > > https://lists.sourceforge.net/lists/listinfo/sdcc-user > > |
From: Dave M. <mc...@ne...> - 2003-03-14 17:39:26
|
On Thursday, March 13, 2003, at 10:15 PM, Jesus Calvino-Fraga wrote: > Also, do you think a design from 1995 (look at the title box) would > still be around if it were incorrect? Heh...that never stopped Microsoft. ;) [sorry, couldn't resist] -Dave -- Dave McGuire "I've grown hair again, just St. Petersburg, FL for the occasion." -Doc Shipley |
From: Rod B. <ro...@bo...> - 2003-03-14 18:44:21
|
I'll just get my hat cooked and server up to me you are correct. The design when looked at more closely would work. Regards, Rod Boyce. On Thu, 13 Mar 2003 19:15:45 -0800 Jesus Calvino-Fraga <Je...@ec...> wrote: > http://www1.uni-bremen.de/~g16i/gifs/sp485.gif |
From: Peter B. <alt...@go...> - 2003-03-14 09:03:38
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I sent the link only to see using the 3 NAND gates. Perhaps it's not the finest schematic I ever seen, but I think it works. I use a very similar circuit for 80C552. You can easily find other schematics on the net, like these for AT89C52: http://www.kmitl.ac.th/~kswichit/C52evbv2/C52reference.pdf http://www.geocities.com/sayabisa51/single_layer.htm Peter ########################################### Ezt a levelet az F-Secure Anti-Virus for Internet Mail ellenõrizte. Miskolci Egyetem Számítóközpont |