# CIIC Harness  

A template SoC for Google SKY130 free shuttles. It is still WIP. The current SoC architecture is given below.

<p align=”center”>
<img src="/doc/ciic_harness.png" width="75%" height="75%"> 
</p>

## Getting Started:

Start by cloning the repo and uncompressing the files.
```bash
git clone https://github.com/efabless/caravel.git
cd caravel
make uncompress
```

Then, you can learn more about the caravel chip by watching these video:
- Caravel User Project Features -- https://youtu.be/zJhnmilXGPo
- Aboard Caravel -- How to put your design on Caravel? -- https://youtu.be/9QV8SDelURk
- Things to Clarify About Caravel -- What versions to use with Caravel? -- https://youtu.be/-LZ522mxXMw

## Aboard Caravel:
### Versions:
- [OpenLANE](https://github.com/efabless/openlane) rc4 or rc5.
- latest [Skywater-pdk](https://github.com/google/skywater-pdk).
    - sky130_fd_sc_hd
    - sky130_fd_sc_hvl
    - sky130_fd_io
- latest [open_pdks](https://github.com/RTimothyEdwards/open_pdks).

Your area is the full user_project_wrapper, so feel free to add your project there or create a differnt macro and harden it seperately then insert it into the user_project_wrapper.

If you will use OpenLANE to harden your design, go through the instructions in this [README.md][0].

Then, you will need to put your design aboard the Caravel chip. In the Caravel directory, make sure you have the following:

- Magic installed on your machine. We may provide a Dockerized version later.
- You have your user_project_wrapper.gds under `./gds/` directory.

Run the following command:

```bash
export PDK_ROOT=<The place where the installed pdk resides>
make
```

This should merge the GDSes using magic and you'll end up with your version of `./gds/caravel.gds`.

## Managment SoC
The managment SoC runs firmware that can be used to:
- Configure User Project I/O pads
- Observe and control User Project signals (through on-chip logic analyzer probes)
- Control the User Project power supply

The memory map of the management SoC can be found [here](verilog/rtl/README)

## User Project Area
This is the user space. It has limited silicon area (TBD, about 3.1mm x 3.8mm) as well as a fixed number of I/O pads (37) and power pads (10).  See [the Caravel  premliminary datasheet](doc/caravel_datasheet.pdf) for details.
The repository contains a [sample user project](/verilog/rtl/user_proj_example.v) that contains a binary 32-bit up counter.  </br>

<p align=”center”>
<img src="/doc/counter_32.png" width="50%" height="50%">
</p>

The firmware running on the Management Area SoC, configures the I/O pads used by the counter and uses the logic probes to observe/control the counter. Three firmware examples are provided:
1. Configure the User Project I/O pads as o/p. Observe the counter value in the testbench: [IO_Ports Test](verilog/dv/caravel/user_proj_example/io_ports).
2. Configure the User Project I/O pads as o/p. Use the Chip LA to load the counter and observe the o/p till it reaches 500: [LA_Test1](verilog/dv/caravel/user_proj_example/la_test1).
3. Configure the User Project I/O pads as o/p. Use the Chip LA to control the clock source and reset signals and observe the counter value for five clock cylcles:  [LA_Test2](verilog/dv/caravel/user_proj_example/la_test2).

[0]: openlane/README.md