This is the repository for an 8-bit computer system that is built using cards with a standardized interface.
- CPU card
- Protoboard card
- This card contains an onboard clock generator, address and data registers/buffers, and a protoboard area for testing designs.
- Bus interface modeling
Here's an example of a card:
// The main bus wires (32+8=40 wires total)
// On the bus connector, all buses have LSBs closer to the power pins and MSBs farther away
wire VCC_5V;
wire GND;
wire clk; // generated by motherboard clock generator
wire rst_n; // probably a button on the motherboard
wire VCC_3V3;
wire we_n; // active LOW
wire oe_n; // active LOW
wire int_n; // pulled up by motherboard; driven down by any peripheral (could be used for interrupts)
wire [7:0] data;
wire [15:0] addr; // 64k address space is suppored by default. More address bits may be added later
wire [7:0] aux_bus;