updated READMEs

Author: ccattuto

README.md

@@ -13,7 +13,7 @@ This is a simple and readable **RISC-V RV32I emulator** written in pure Python.
 - **Supports memory-mapped IO** and provides a **UART peripheral** using a pseudo-terminal, and a **memory-mapped block device** backed by an image file
 - **Passes all `rv32ui` and `rv32mi` unit tests** provided by [RISC-V International](https://github.com/riscv-software-src/riscv-tests)
 - **Supports logging** of register values, function calls, system calls, traps, invalid memory accesses, violations of invariants
-- Runs [MicroPython](https://micropython.org/) and [FreeRTOS](https://www.freertos.org/) with preemptive multitasking
+- Runs [MicroPython](https://micropython.org/), [CircuitPython](https://circuitpython.org/) with emulated peripherals, and [FreeRTOS](https://www.freertos.org/) with preemptive multitasking
 - Self-contained, modular, extensible codebase
 
 ## 🔧 Requirements
@@ -51,8 +51,9 @@ pip install -r requirements.txt
 ├── prebuilt/                  # Pre-built examples
 ├── run_unit_tests.py          # Runs RISC-V unit tests (RV32UI and RV32MI)
 ├── riscv-tests/               # Git submodule with RISC-V unit tests
-├── advanced/micropython/      # MicroPython port
 ├── advanced/freertos/         # FreeRTOS port
+├── advanced/micropython/      # MicroPython port
+├── advanced/circuitpython/    # CircuitPython port
 └── README.md                  # You're here!
 ```
 

advanced/circuitpython/README.md

@@ -1,11 +1,53 @@
 ## Compiling CircuitPython
+
 ```
 cd port-riscv-emu.py
 make
 ```
 
 ## Running CircuitPython
+
+Run the emulator:
 ```
 ./riscv-emu.py --timer=mmio --ram-size=4096 --uart --blkdev=advanced/circuitpython/riscv-emu.py/build-riscv-emu.py/circuitpy.img advanced/circuitpython/riscv-emu.py/build-riscv-emu.py/firmware.elf
+000.001s [INFO] [UART] PTY created: /dev/ttys007
+000.002s [INFO] [BLOCK] Opening block device image: advanced/circuitpython/riscv-emu.py/build-riscv-emu.py/circuitpy.img
 ```
 
+Connect to CircuitPython using your favorite terminal program:
+```
+screen /dev/ttys007 115200
+```
+
+This CircuitPython port supports an emulated serial backed by a pseudoterminal, an emulated block device backed by a filesystem image, interrupt-driven timer and tick support, CTRL+C support for tight Python loops, autoreload, and more:
+```
+Adafruit CircuitPython 9.2.7-dirty on 2025-05-19; riscv-emu.py with riscv-emu.py
+>>> import sys
+>>> sys.platform
+'riscv-emu.py'
+>>> import os
+>>> os.listdir("/")
+['code.py']
+>>> import time
+>>> time.monotonic()
+23.779
+>>> time.monotonic()
+24.765
+>>> time.sleep(1)
+>>> while True:
+...     pass
+...     
+...     
+... 
+Traceback (most recent call last):
+  File "<stdin>", line 2, in <module>
+KeyboardInterrupt: 
+>>> help("modules")
+__future__        busio             micropython       struct
+__main__          collections       os                supervisor
+array             gc                rainbowio         sys
+board             math              random            time
+builtins          microcontroller   storage
+Plus any modules on the filesystem
+>>> 
+```