usb转串口软件IO模拟串口UART 树莓派_Raspberry-Pi

关于raspberry pico通过usbcdc来实现串口功能的问题

发布于 2022-02-14 21:58:07 浏览：2401 订阅该版

2 个回答

嵌入式史迪奇 2022-02-17

这家伙很懒，什么也没写！

对着tinyusb的CMake扒了下，可以build成功了，并且printf可以成功打印到串口
但是rt_kprintf还不工作。。后续再研究其实现原理

![4d9df53285b432543c7b9147a0ebf925.png.webp](https://oss-club.rt-thread.org/uploads/20220217/4d9df53285b432543c7b9147a0ebf925.png.webp)

需要修改libraries/SConscript文件，添加以下部分
```python
src = src + Split("""
pico-sdk/src/rp2_common/pico_stdio_usb/stdio_usb.c
pico-sdk/src/rp2_common/pico_stdio_usb/stdio_usb_descriptors.c
pico-sdk/lib/tinyusb/src/tusb.c
pico-sdk/lib/tinyusb/src/common/tusb_fifo.c
pico-sdk/lib/tinyusb/src/portable/raspberrypi/rp2040/dcd_rp2040.c
pico-sdk/lib/tinyusb/src/portable/raspberrypi/rp2040/rp2040_usb.c
pico-sdk/lib/tinyusb/src/device/usbd.c
pico-sdk/lib/tinyusb/src/device/usbd_control.c
pico-sdk/lib/tinyusb/src/class/audio/audio_device.c
pico-sdk/lib/tinyusb/src/class/cdc/cdc_device.c
pico-sdk/lib/tinyusb/src/class/dfu/dfu_device.c
pico-sdk/lib/tinyusb/src/class/dfu/dfu_rt_device.c
pico-sdk/lib/tinyusb/src/class/hid/hid_device.c
pico-sdk/lib/tinyusb/src/class/midi/midi_device.c
pico-sdk/lib/tinyusb/src/class/msc/msc_device.c
pico-sdk/lib/tinyusb/src/class/net/ecm_rndis_device.c
pico-sdk/lib/tinyusb/src/class/net/ncm_device.c
pico-sdk/lib/tinyusb/src/class/usbtmc/usbtmc_device.c
pico-sdk/lib/tinyusb/src/class/vendor/vendor_device.c
pico-sdk/lib/tinyusb/src/class/video/video_device.c
pico-sdk/lib/tinyusb/hw/bsp/rp2040/family.c
pico-sdk/src/rp2_common/pico_fix/rp2040_usb_device_enumeration/rp2040_usb_device_enumeration.c
""")

path = path + [
    cwd + '/pico-sdk/lib/tinyusb/src',
    cwd + '/pico-sdk/lib/tinyusb/src/common',
    cwd + '/pico-sdk/lib/tinyusb/hw',
    cwd + '/pico-sdk/src/rp2_common/pico_fix/rp2040_usb_device_enumeration/include'
]

CPPDEFINES = CPPDEFINES + [
    'CFG_TUSB_MCU=OPT_MCU_RP2040',
    'CFG_TUSB_OS=OPT_OS_PICO',
    'PICO_RP2040_USB_DEVICE_ENUMERATION_FIX=1',
    'PICO_STDIO_USB=1',
]
```

下面两个文件的修改主要是因为rt thread里的pico sdk和pico sdk主分支代码有差异造成的build error，临时添加差异代码作为workaround
1.修改libraries/pico-sdk/src/common/pico_stdlib/include/pico/stdlib.h文件，添加如下
```
 // PICO_CONFIG: PICO_DEFAULT_LED_PIN_INVERTED, 1 if LED is inverted or 0 if not, type=int, default=0, group=pico_stdlib
 #ifndef PICO_DEFAULT_LED_PIN_INVERTED
 #define PICO_DEFAULT_LED_PIN_INVERTED 0
 #endif
```

2.修改libraries/pico-sdk/src/rp2_common/pico_stdio_usb/stdio_usb.c文件，添加如下
```c
#include "pico/mutex.h"
```