Pyramiden Core - 16-bit RV16U Microcore Processor

This is a CPU core based on the RISC-V ISA reduced in size to support 16-bit data and memory operations with 21-bit instructions and 16 registers. The full RISC-V base instruction set is supported with the exception of the CSRs which were removed. The design uses a Harvard memory architecture. The design project evolved from a submission for the Tiny Tapeout project where an 8-bit processor was implemented. The external memory interface for the chip employs a simple serdes to accomodate the limited I/O pins available. This reduces the effective processor clock by 8x in order to synchronize the instruction and data memory interfaces. This was a compromise that evolved as a solution to interface the chip to the larger I/O interface of the processor core.

I/O Pins

Inputs:

- clock
- reset
- enable
- imem_rdy
- dmem_bsy
- dmem_rdy
- serdes input bit 0
- serdes input bit 1
- serdes input bit 2
- serdes input bit 3
- serdes input bit 4
- serdes input bit 5
- serdes input bit 6
- serdes input bit 7
- serdes input bit 8
- serdes input bit 9
- serdes input bit 10
- serdes input bit 11
- serdes input bit 12

Outputs:

• halt
• dmem_we
• dmem_en
• serdes output bit 0
• serdes output bit 1
• serdes output bit 2
• serdes output bit 3
• serdes output bit 4
• serdes output bit 5
• serdes output bit 6
• serdes output bit 7
• serdes output bit 8
• serdes output bit 9
• serdes output bit 10
• serdes output bit 11
• serdes output bit 12
• serdes output bit 13
• serdes output bit 14
• serdes output bit 15

Tiny User Project

(Below are the original instructions used to submit the design.)

Template for submitting TinyTapeout based projects to the Open MPW shuttle program.

Usage

1. Generate a new project based on this template

2. Set GitHub Pages Sources as GitHub Actions.

3. Create a new Wokwi project.

4. Update info.yaml with your wokwi_id and make sure the documentation for inputs and outputs matches the Wokwi design.

5. Commit, push and check the workflow summary (if successful a new commit including the hardened files will be automatically created).

6. Submit your project github repository to the next Open MPW shuttle.