# DSPi RP2350 v1.1.5 artifact evidence

Checked on October 18, 2026. This record describes published files and source definitions. No board was flashed or measured.

## Release artifact

The [stable DSPi v1.1.5 release](https://github.com/WeebLabs/DSPi/releases/tag/v1.1.5) provides [DSPi-RP2350-v1.1.5.uf2](https://github.com/WeebLabs/DSPi/releases/download/v1.1.5/DSPi-RP2350-v1.1.5.uf2). The source tag resolves to commit `5d4dd00f82637fdf8d275f80aeaff0fd7b62719a`.

The downloaded file contains 485888 bytes. Its SHA-256 is `6fc2be5f877e7d7aa807aeec4d0f1afe82c171c6d2c0f0047b515c6746385e60`. This matches the digest reported for asset 500685172 in the [GitHub release API](https://api.github.com/repos/WeebLabs/DSPi/releases/tags/v1.1.5).

The local copy is `DSPi-RP2350-v1.1.5.uf2`. The complete `picotool info -a` output is stored in `dspi-rp2350-v1.1.5-uf2-info.txt`. It identifies RP2350, ARM Secure, SDK 2.2.0, board `pico2`, a Release build dated August 4, 2026, and program addresses from `0x10000000` through `0x1003b380`.

All 949 UF2 blocks passed the file-format magic checks. There are 948 RP2350 ARM Secure blocks with family ID `0xe48bff59`, plus one absolute-address block with family ID `0xe48bff57` at `0x10ffff00`. The latter is not treated as evidence of a 16 MiB program or physical flash. The family names come from Microsoft's [UF2 family registry](https://github.com/microsoft/uf2/blob/master/utils/uf2families.json).

## Documented flash configuration

The [Waveshare wiki](https://www.waveshare.com/wiki/RP2350-Zero#Features) specifies 4 MB of flash for RP2350-Zero. Both SDK 2.2.0 headers, [waveshare_rp2350_zero.h](https://github.com/raspberrypi/pico-sdk/blob/2.2.0/src/boards/include/boards/waveshare_rp2350_zero.h) and [pico2.h](https://github.com/raspberrypi/pico-sdk/blob/2.2.0/src/boards/include/boards/pico2.h), define `PICO_FLASH_SIZE_BYTES` as `4 * 1024 * 1024`.

The SDK submodule used by the DSPi tag is `a1438dff1d38bd9c65dbd693f0e5db4b9ae91779`. Its two board headers are byte-identical to those in SDK 2.2.0.

DSPi's [flash geometry definitions](https://github.com/WeebLabs/DSPi/blob/v1.1.5/firmware/DSPi/flash_storage.c#L64-L90) reserve 21 sectors for RP2350 presets at the end of the configured flash. With 4096-byte sectors and 4 MiB flash, that region spans offsets `0x3eb000` through `0x3fffff`.

This is a match between the published 4 MiB board specification and the firmware's board configuration, not a reading of the user's physical flash chip. The linked Waveshare schematic labels its flash `W25Q16JVUXIQ`; it is not used to claim a measured capacity for the delivered module. The paper's firmware reference is explicitly limited to the 4 MiB specification.

## Clock limitation

The [RP2350 product brief, page 3](https://datasheets.raspberrypi.com/rp2350/rp2350-product-brief.pdf) specifies 150 MHz. The complete brief is stored locally as `rp2350-product-brief.pdf`.

DSPi v1.1.5 [core0_init()](https://github.com/WeebLabs/DSPi/blob/v1.1.5/firmware/DSPi/main.c#L1650-L1675) requests 307200000 Hz and falls back to 150000000 Hz only if the clock-setting function reports failure. The normal request exceeds the published 150 MHz specification. The fallback is not described as a hardware stability test.

The paper must not call this release an in-spec 150 MHz configuration or claim physical stability from the file inspection.

## Installation and I2S

The [Waveshare flashing instructions](https://www.waveshare.com/wiki/RP2350-Zero#Flash_Firmware_2) describe holding BOOT while connecting USB and copying the UF2 to the resulting USB drive. [UF2](https://github.com/microsoft/uf2) is a firmware file format for this mass-storage flashing method.

DSPi's [I2S output specification](https://github.com/WeebLabs/DSPi/blob/v1.1.5/Documentation/Features/i2s_output_spec.md) defines slot 0, data GPIO6, BCK GPIO14, and LRCLK GPIO15. MCK is optional. The [hardware-mute implementation](https://github.com/WeebLabs/DSPi/blob/v1.1.5/firmware/DSPi/dac_hw_mute.c) permits the feature to be disabled. This does not require a GP2 wire for digital audio output.