GottaGoFastRAM 8MB Autoconfig Fast RAM
This is an 8MB Autoconfig Fast RAM for Amiga 500/1000/2000/CDTV based on mkl's mem68k
It's small size allows it to be stacked on top of an ide68k board
Rather than use the original mem68k Abel code I have written a new memory controller in Verilog
Table of contents
Ordering PCBs
I recommend ordering the PCB with a 0.6 or 0.8mm thickness if you intend on stacking with an ide68k or mouting using a DIP socket/machined pin strips.
If you are going to mount using the socket pins and not stacking with an ide68k I'd recommend going with the usual 1.6mm to reduce flexing.
Mounting options
- Can be soldered to the bottom of a machined pin socket/machined pin strips (will require some cutting of the dip socket to fit the caps/ferrites near the plastic)
Cfgin/out
These pins allow you to insert the memory module into your autoconfig chain.
If there are no other autoconfig devices in your system you can just leave these unconnected otherwise you will need to either connect CFGOut to the CFGin of the first device in your existing autoconfig chain, or connect CFGIn to the CFGOut pin of the last device in your existing autoconfig chain.
You can also connect cfgin and cfgout with a jumper to disable the device temporarily
Jumpers
J1: Cfgin pull up/down (You will probably want to leave this at default unless you know what you're doing)
J2-3: Bridge these if you have not fitted the buffer U4
CDTV
The CDTV's DMAC takes up the first autoconfig slot, so if you intend to use this with a CDTV use the CDTV specific .JED file to program the CPLD
Timing Diagrams
Bill of materials
Component | Location | QTY | Link | Remarks |
---|---|---|---|---|
4Mx16 3V DRAM TSSOP - K4E641612D or GM71VS65163 | U3 | 1 | - | eBay/Aliexpress etc. |
XC9572XL-10VQ64C | U1 | 1 | Mouser | |
74LVC2G17 | U4 | 1 | Mouser | |
AP2210N-3.3 | U5 | 1 | Mouser | |
74LVC245N TSSOP | U6,U7 | 2 | Mouser | |
Ferrite Bead, 1206 package | FB1, FB2 | 2 | Mouser | |
10K Resistor, 0603 | R1 | 1 | Mouser | |
0.1uF Ceramic Capacitor, 0603 | C1,4-13 | 11 | Mouser | |
4.7uF Ceramic Capacitor, 1206 | C2 | 1 | Mouser | |
10uF Ceramic Capacitor, 1206 | C3 | 1 | Mouser | |
Socket pins | Pins | 64 | Aliexpress | Use these if stacking with an ide68k module |
64-Pin DIP socket - machined pin | Pins | 1 | Mouser | If not stacking with ide68k - pcb can be soldered to bottom of this flush with the plastic |