unebonnevie

Hi, Below is the memory map for the 2600. So, for the ROM itself, first byte of the game's program is stored at zero address of the ROM? The Atari 2600's 6507 CPU would read the first byte of the ROM via the instruction like LDA $F000 and the RIOT chip would map that to first address (the zeroth address) of the ROM? 0000-002C TIA (Write) 0030-003D TIA (Read) 0080-00FF RIOT RAM 0280-0297 RIOT I/O, TIMER F000-FFFF ROM

Thanks! I found the site http://www.grandideastudio.com/portfolio/pixels-past/, which the explanation AND the PCB and schematic files as well.

I saw Space Rocks and WOW! It's a 32KB ROM. I frankly didn't know that the Atari 2600 can take 32KB ROM. How is that wired? Thanks!

Hi, I have an Atari 800XL, bought from eBay. The power supply's cord is a bit wiggle (not well connected) to the brick. How do I open the brick itself and make sure the cord is well connected? Thanks!

Sorry for an off beat question: But does anyone know of the pitch for the Vectrex 36-pin (18 pins on each side) edge connector. I am looking to buy an edge connector from eBay to replace my Vector's edge connector, but wanted to make sure I get the right pitch. Thanks!

Ksarul, I would like to buy one of the bare board. Please PM email where to send the money and how much. I assume there is no CPLD/GAL chips are needed in your 128Kx4 project? Haven't looked at the schematic you attached yet.

Sounds like a group hug is in order!

@jdgabbard: Nothing wrong of converting the ExpressPCB files to EagleCAD, as long as the EagleCAD will open source like [email protected] did for his ExpressPCB release. Thank you! [email protected], where can I check out/download your ExpressPCB design? Please consider giving [email protected] permission. I think I can do it on EagleCAD. Anyone knows what the spacing between pads for the TI cartridge? I guess I could open one and measure. Thank you both!

Thank you, all. One more question: Is there EagleCAD part available for TI99/4A's cartridge?

Hi, TI99/4A newbie! And looking to do my own cartridge. Please see http://www.hardwarebook.info/TI-99/4A_Cartridge_Port. I have some questions: 1) Differences between ROMG (pin 34) and GROM address range, pin 21? Pin 34 is where the cartridge code is going to be? GROM? 2) GROM ready, pin 35. What does it really mean? 3) The cartridge is read when pin 25 is HIGH and pin 34 go LOW? 3) What is "CRU" from pin 4? Thank you!

Is 0.1" (2.54mm)? Thank you! I am trying to see if I can do a RAM expansion board through the cartridge port or the expansion port. It seems like I have to have something called the PEB (TI's original expansion board) to do a RAM expansion board through the expansion port? Or, as another choice, I can do a RAM expansion via the cartridge port? Thanks!

Thank you, all for the info!

Hi, I would like to know the pitch of the 44-pin expansion port of the TI99/4A, so that I can buy a connector for it. I am looking to make a 32KB expansion board. Is that possible? I see people modding the TI99/4A to 32KB. Would like to see the schematic if anyone knows. Thanks!