xfyun_tts/
├── code/
│   ├── xfyun_tts.py    # 驱动核心实现
│   └── main.py         # 使用示例 / 测试代码
├── package.json        # mip 包配置（含依赖声明）
├── README.md           # 使用文档
└── LICENSE             # MIT 开源协议

获取当前 UTC 时间（RFC1123 格式，依赖 NTP 同步）
    ↓
构造签名原文：
    "host: tts-api.xfyun.cn\n
     date: {RFC1123 时间}\n
     GET /v2/tts HTTP/1.1"
    ↓
HMAC-SHA256(API Secret 的 UTF-8 字节, 签名原文) → 32 字节摘要
    ↓
Base64 编码 → signature 字符串
    ↓
构造 authorization 原文 → Base64 编码 → URL 百分号编码
    ↓
拼入 WSS 查询字符串：?authorization=...&date=...&host=...

打开文件（"wb"）
    ↓
若后缀为 .wav：写入 44 字节占位头（data_size = 0）
    ↓
循环接收音频帧（每帧约 1~4 KB）→ 立即 f.write(chunk)
    ↓
接收完毕（服务端 status == 2）
    ↓
若 .wav：f.seek(0) 回填真实 data_size → 标准 WAV 文件完成
    ↓
关闭文件

mpremote mip install https://upypi.net/pkgs/async_websocket_client/1.0.0

mpremote cp code/xfyun_tts.py :xfyun_tts.py

import ntptime
ntptime.host = "ntp.aliyun.com"
ntptime.settime()

from xfyun_tts import XfyunTTS

tts = XfyunTTS(
    app_id     = "your_appid",
    api_key    = "your_api_key",
    api_secret = "your_api_secret",  # 平台提供的原始字符串，勿 Base64 解码
)

import asyncio

# 输出 RAW PCM 文件
total = asyncio.run(tts.synthesize("Hello World", filepath="output.pcm"))
print(total, "bytes written")

# 输出 WAV 文件（直接可在 PC 上播放）
total = asyncio.run(tts.synthesize("Hello World", filepath="output.wav"))
print(total, "bytes PCM + 44 bytes header")

# 极短文本：不写文件，返回 bytes（仅适合极短文本）
pcm_bytes = asyncio.run(tts.synthesize("Hi"))

# Python env   : MicroPython v1.23.0
# -*- coding: utf-8 -*-
# @Time    : 2026/04/12
# @Author  : leeqingsui
# @File    : main.py
# @Description : iFlytek TTS usage example for MicroPython on Raspberry Pi Pico 2W
# @License : MIT

import network
import asyncio
import time
import ntptime
from xfyun_tts import XfyunTTS

WIFI_SSID     = "your_wifi_ssid"
WIFI_PASSWORD = "your_wifi_password"

APPID      = "your_appid"
API_KEY    = "your_api_key"
API_SECRET = "your_api_secret"

OUTPUT_FILE = "output.pcm"
OUTPUT_WAV  = "output.wav"

def connect_wifi():
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)
    if not wlan.isconnected():
        wlan.connect(WIFI_SSID, WIFI_PASSWORD)
        timeout = 15
        while not wlan.isconnected() and timeout > 0:
            time.sleep(1)
            timeout -= 1
        if not wlan.isconnected():
            return None
    return wlan

def sync_ntp():
    for host in ("ntp.aliyun.com", "ntp.tencent.com", "pool.ntp.org"):
        try:
            ntptime.host = host
            ntptime.settime()
            print("NTP synced via", host)
            return
        except Exception as e:
            print("NTP failed:", e)

async def run_tts(text):
    total = await tts.synthesize(text, filepath=OUTPUT_FILE)
    print("Saved", total, "bytes ->", OUTPUT_FILE)

async def run_tts_wav(text):
    total = await tts.synthesize(text, filepath=OUTPUT_WAV)
    print("Saved", total, "bytes PCM +44 bytes header ->", OUTPUT_WAV)

tts = XfyunTTS(app_id=APPID, api_key=API_KEY, api_secret=API_SECRET)

if __name__ == "__main__":
    time.sleep(3)
    print("--- FreakStudio iFlytek TTS Demo ---")
    if not connect_wifi():
        print("Aborting: WiFi unavailable.")
    else:
        sync_ntp()
        asyncio.run(run_tts("Hello, I am Xiaozhi. Nice to meet you."))
        asyncio.run(run_tts_wav("Hi there, this is a WAV format test from Pico 2W."))

--- FreakStudio iFlytek TTS Demo ---
WiFi already connected
NTP synced via ntp.aliyun.com
Synthesizing: Hello, I am Xiaozhi. Nice to meet you.
Connecting to iFlytek TTS...
Connected, sending request...
Receiving audio chunks...
Chunk received, bytes: 3200
Chunk received, bytes: 3200
...
All audio received, total bytes: 62400
Saved 62400 bytes -> output.pcm
Synthesizing (WAV): Hi there, this is a WAV format test from Pico 2W.
...
All audio received, total bytes: 57600
Saved 57600 bytes PCM +44 bytes header -> output.wav

MIT License

Copyright (c) 2026 FreakStudio

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.