So I know enough about electronics and the Z80 to have most of the basics, but I have some important questions that I can't seem to find answers to.
1. If I have a 2732 EPROM, how do I wire CE, OE, and A11? I think A11 just goes to A11 on the Z80 but I can't find anything to confirm it.
2. Do I need the DMA or CTC chips?
3. How would I wire a TMS9918 and a SN76489 to the CPU?
4. Can I get by only using two RAM chips or do I need 8 to fill all of the digital pins?
5. What does the DART chip do/how does it connect to the CPU?
6. I have two 4264 RAM chips. how do I connect WE, RAS, and CAS?
Thanks! I'll probably have more questions over time, but these are the important ones for now.
Somehow, I don't think your first statement is right. You are asking questions that show that you clearly don't know enough about electronics.
1. A11
If you want to use the full address space of your 2732 you have to connect A11 to something. Connecting to the processor A11 is clearly an option. If you just connect it to ground, you'll only have 1/2 the available EPROMs address space. You might connect it to another address, say A15, if you want half of the EPROM in the low part of memory and half in the high part. Most people just use it as a continuous block of memory, as seen by the processor.
OE is usually connected to the inverse of the write enable from the processor and CE is connected to an address decoder of the remaining part of the address, A12 to A15. One can tie OE and combine the address decode with the write signal into CE. Before you get too far, the signals on a 2732 are OE* and CE* indicating that they are active low, not active high. This means the logic that selects them must be 0 when it is selected. A common address decoder is a 74138 or a 74688, depending on how you want to do it.
Get the copy of the spec sheets for each part you want to use. Look at the timing diagrams until you understand them.
2. I doubt you'll need a DMA chip in a simple system. A CTC is one way to get to the outside world. It would be convenient.
3. Connecting a video chip is beyond what count be done in a few lines of text. Again, look for data sheets and possibly ap notes.
4. 6. Combined: It would be really difficult to do much with 2 bits out of 8 data bits for RAM. It would clearly be an exercise beyond what you will be able to deal with. DRAM, as mentioned by another is not a good idea for a first project. The Z80 can do DRAM but be careful as the Z80 can only directly do 128 cycle refresh and some 64K DRAM need 256 cycle. It is especially bad as they use the same part numbers. I also recommend getting 8 bit SRAMs. They are connected to the bus, similar to the EPROM. Usually they are not a full 64K making it easier to have mixed EPROM and SRAM on the same address space.
5. DART is just two serial chips in one package. Again, refer to data sheets!
6 answered at 4.
It seems clear that you don't fully understand the concepts of addressing. Each device on the bus needs a specific address space defined by some form of decoder logic. The Z80 is a bit more difficult than say a 6502 in that it has 2 address spaces. It has an I/O address space and a main instruction/data address space. One typically connects I/O devices using the I/O addressing but there is no hard rule that says you need to do that.
Again, spend some time looking at the data sheets. Should you decide to to get 6 more DRAMs, you might study the schematics of some other simple computers. You might look at things like the ZX80/ZX81 computers. Another is the Jupiter Ace. These are about as simple as you can get using DRAM.
Dwight
