tag:blogger.com,1999:blog-5261990937291835648.post405983966968612102..comments2023-12-13T12:21:47.178+02:00Comments on Peten Paja: VIC-20 Flash Memory Programmer Part 1/2Anonymoushttp://www.blogger.com/profile/16877976762002867526noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-5261990937291835648.post-30605101339397850242023-11-19T09:30:11.792+02:002023-11-19T09:30:11.792+02:00That's cool! Since you don't connect the ...That's cool! Since you don't connect the /W line, you can use a RAM chip. It also means the trick commodore does on reset, writing to the ROM area won't change your program code because your program area isn't written to... Win / Win !Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5261990937291835648.post-934448163996397022018-10-07T19:33:55.711+03:002018-10-07T19:33:55.711+03:00How To I Burn A Vic @0 Cartrige Image To Eprom
How To I Burn A Vic @0 Cartrige Image To Eprom<br />Anonymoushttps://www.blogger.com/profile/06054099764215833599noreply@blogger.comtag:blogger.com,1999:blog-5261990937291835648.post-30658914830886594172014-05-07T03:42:51.078+03:002014-05-07T03:42:51.078+03:00>If you wire the address lines directly to the ...>If you wire the address lines directly to the ROM chip, the ROM image should be loaded starting at address 0. /BLK5 will be pulled low when VIC is accessing the memory block starting at address $A000. This will automatically map $A000 in VIC's address space to 0 in your ROM.<br /><br />Thanks for the confirmation. I just wanted to be sure, as all cartridges ROMs go from address. Good to know that the VIC20 has address decoding logic when /BLK5 is pulled low.<br /><br />Thanks again!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5261990937291835648.post-67080291305292047952014-05-05T12:26:48.984+03:002014-05-05T12:26:48.984+03:00>should I dump the ROM image into my flash chip...>should I dump the ROM image into my flash chip starting at address 0x0000 or 0xA000?<br />If you wire the address lines directly to the ROM chip, the ROM image should be loaded starting at address 0. /BLK5 will be pulled low when VIC is accessing the memory block starting at address $A000. This will automatically map $A000 in VIC's address space to 0 in your ROM.<br /><br />I simply ignore VIC's R/W signal because VIC can't write to the ROM anyway. I connect /BLK5 to /OE and let the MCU control the /CE and /WE signals needed for updating the ROM. If you don't need to update the ROM on the fly, you can hardwire /CE to low and /WE to high and let the VIC the control /OE. I use the buffer chips to disconnect the ROM from the address and data busses of the VIC20 when I'm uploading new code to ROM.<br /><br />Also please see the schematic in the blog post. Hope this helps!<br />Anonymoushttps://www.blogger.com/profile/16877976762002867526noreply@blogger.comtag:blogger.com,1999:blog-5261990937291835648.post-83762104863458250852014-05-04T22:19:00.552+03:002014-05-04T22:19:00.552+03:00One additional question.
Do you connect the VIC2...One additional question. <br /><br />Do you connect the VIC20's C R/W pin (pin #18 on the cartridge) to your flash's /OE pin? Note that for the VIC20's, a HIGH means READ. The flash's /OE pin must be connected to an inverter from the VIC20's C R/W pin.<br /><br />Looking at your cartridge image, looks like the VIC20's C R/W is not connected at all, because the cartridge uses a 24-pin EPROM, which does not have the /OE pin.<br /><br />Just wondering what your flash IC's /OE pin is connected to.<br /><br />Thanks!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5261990937291835648.post-51131156552128591922014-05-04T22:08:45.055+03:002014-05-04T22:08:45.055+03:00Thank you very much!
I bought a VIC20 cartridge ...Thank you very much! <br /><br />I bought a VIC20 cartridge board on eBay ( search for item # 111338337060).<br /><br />I hook up that board to my breadboard and I use the PDIP flash chip SST39F040, which is 512Kx8 flash chip.<br /><br />And I dump an 8K rom into the flash chip from address 0 to 8191, 8KB total.<br /><br />I understand that the VIC20's cartridge area starts at address 0xA000. So, should I dump the ROM image into my flash chip starting at address 0x0000 or 0xA000?<br /><br />In my attempt, I tried to connect /BLK5 to GND and also my flash IC's /CE pin to GND, but that is wrong as you indicated. The /BLK5 needs to be connected to the flash IC's /CE pin for the VIC20 to activate it during boot up and inactivate if no cartridge program is found.<br /><br />By having /BLK5 connected to the flash's IC /CE pin, my VIC20 does not hang now and boots up but does not detect a cartridge.<br /><br />Thanks!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5261990937291835648.post-44279783493095451662014-05-04T10:19:20.305+03:002014-05-04T10:19:20.305+03:00Hello! Pins 12 and 13 are memory block selection s...Hello! Pins 12 and 13 are memory block selection signals. Do not connect these pins to ground!<br /><br />Pin 12 is left unconnected. Pin 13, active low, selects the ROM memory block starting at address $A000. In cartridge games it is normally connected to the chip select pin of the ROM chip. In my schematic it is connected to the 74HC541 buffers, IC1-IC3.<br /><br />Hope this answered your question!Anonymoushttps://www.blogger.com/profile/16877976762002867526noreply@blogger.comtag:blogger.com,1999:blog-5261990937291835648.post-22788367019001927742014-05-03T20:34:40.338+03:002014-05-03T20:34:40.338+03:00Could you please tell me what the J1 / J2, that is...Could you please tell me what the J1 / J2, that is, pin #12 or #13 top side of the cartridge, trace line connected to? Is that connected to ground?<br /><br />Thank you!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5261990937291835648.post-546104373895335552014-04-03T09:14:22.633+03:002014-04-03T09:14:22.633+03:00Instead the Arduino board you could use a MAX232 c...Instead the Arduino board you could use a MAX232 chip and then interface the board with any computer equipped with a USB port.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5261990937291835648.post-66884792008723617132014-02-01T18:43:46.781+02:002014-02-01T18:43:46.781+02:00excellent!excellent!Anonymousnoreply@blogger.com