Right, last year I got a stupid Idea.
I am going to build a computer based on ECL-Logic, furthermore it is going to be of completly discrete components.
My goal is to build an at least 8-bit box running at 100 MHZ.
You will find schematics and PCB layouts on my project site www.microdiscray.com
I havent simulated any logic, so far (thats Why I am here), but as the work progress, I will post the circuits here.
Reason that I havent been simulating it, is that I've been looking for a simulator that can do both Analog and digital simulation at the same time, however that seemes to be impossible, at least for a low cost.
Hopfully I will be posting the circuit of the ALU-Slice tonight.
So, what am I using, well each 1-bit slice is going to sit on one 6-layer PCB, so to assemble a complete ALU, will require 8 PCB-boards.
Each of them in double eurocard format 233x160mm with approximatly 1000 components on each board.
In total there will be some 400 transistors and some 400 resistors on each board, together with some LED's, connectors etc.
After that the ALU is finiched, I will dig into the other logic.
Obviously all comments and advises are very welcome.
MicroDisCray, a stupid project
Re: MicroDisCray, a stupid project
Here is the circuit of the 1-bit Alu-slice.
It will (hopefully) do 7 functions (AND, OR, XOR, NOR, ADD, SUB and SLT).
I had to design my own gates, since Logical Circuit doesn't have any ECL-gates.
The only type of gate used is an OR-gate, however, due to the design of ECL, it has two outputs, the normal one and the complementary output.
Since all gates are open collector, I can Wire-Or them together when needed.
Now this didn't allways work in Logical Circuit, so I had to add an extra input in all my "primitives" connect that input to a 0, so the gate allways defaults to zero.
Each gate consists of a number of transistors and resistors, the amount of transistors is basically the sum of inputs + 3, the same applies to the resistors, thats all that is needed for the gates.
The transistors are normal bipolar HF ones.
Each gate is supplied with 2 voltages, Vee -5.2V and a Vref of 2V, so obviously this is negative logic, i.e a zero is around -2 volts and a 1 is araound -4.5V.
Since the transistors do not switch on/off as in usual Logic circuits, it will not produce any EMC.
ANyway, here is the first circuit.
It will (hopefully) do 7 functions (AND, OR, XOR, NOR, ADD, SUB and SLT).
I had to design my own gates, since Logical Circuit doesn't have any ECL-gates.
The only type of gate used is an OR-gate, however, due to the design of ECL, it has two outputs, the normal one and the complementary output.
Since all gates are open collector, I can Wire-Or them together when needed.
Now this didn't allways work in Logical Circuit, so I had to add an extra input in all my "primitives" connect that input to a 0, so the gate allways defaults to zero.
Each gate consists of a number of transistors and resistors, the amount of transistors is basically the sum of inputs + 3, the same applies to the resistors, thats all that is needed for the gates.
The transistors are normal bipolar HF ones.
Each gate is supplied with 2 voltages, Vee -5.2V and a Vref of 2V, so obviously this is negative logic, i.e a zero is around -2 volts and a 1 is araound -4.5V.
Since the transistors do not switch on/off as in usual Logic circuits, it will not produce any EMC.
ANyway, here is the first circuit.
- Attachments
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- uDisCray.CircuitProject
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Re: MicroDisCray, a stupid project
What is the SET output? Why there is a carry on AND, OR operations?
Re: MicroDisCray, a stupid project
Set is the SLT-operation, Since carry isn't masked, and all operations is performed simultaniously, one cannot avoid carry etc.
A slt B = 0x01 if A<B and 0x00 if A >= B
A slt B = 0x01 if A<B and 0x00 if A >= B