树莓派Pico快速上手教程之MicroPython和C的使用说明

2021年初，树莓派Pico板一面世我就获得了Cytron提供的测试版，并使用微Python和C进行了编程。

当时，我从官方文档件入手，用快速使用树莓派Pico运行Ubuntu 20.04操作系统的计算机入门指南为操作案例，并对每一个细节进行了记录，哪怕是LED闪烁这样微小的事项都被我纳入了收录范围内。这其实与 Windows 和 Mac 操作系统的说明有点类似。

准备硬件

从理论上讲开发板是可以单独使用的，但由于板子有一些接头，因此我便借机尝试使用了一下由MINIX NEO P2 USB-C电源供电的Pining64 Pinecil烙铁。

烙铁工作了大约一分钟，然后就开始出现焊接问题了。看着屏幕，可以看到Zzzz并且温度在下降。因为焊锡不够，所以我没有再移动烙铁，所以未检测到任何活动后它就进入睡眠状态了。不过，更改运动灵敏度或睡眠超时就可以轻松地解决此问题。同时，我也可以完成手头的其他任务了。

不使用这些头让人感觉有点无能，所以我将树莓派Pico插入到面包板，并增加了一个LED与附带的电路。

5V 连接到 VBUS（引脚 40），GND 连接到引脚 38，我决定使用最靠近 LED 的 GPIO 即 GP15（引脚 20）。树莓派Pico上的GPIO标记仅显示在板的底部，当板连接到面包板时，原理图会有所帮助。

硬件设置现已完成，我只需要一个微型 USB转 USB-A 电缆将电路板连接到我的笔记本电脑。

树莓派Pico上的MicroPython

首先，我们应将MicroPython固件烧录到板中。为此，可从入门指南下载最新的固件（审核时为pico_micropython_20210121.uf2）。

其次，在连接到带有 USB 端口的计算机时按板上的 BOOTSEL 键，并在连接后释放按键。我这样做了，但什么也没发生。那是因为我使用自行车灯的USB电缆，缺乏数据线。

最后，我选择一个适当的Micro USB到USB-A型电缆，树莓派Pico顺利在我的笔记本电脑上正确识别了：

[422070.155550] usb 1-2: new full-speed USB device number 16 using xhci_hcd
[422070.330829] usb 1-2: New USB device found, idVendor=2e8a, idProduct=0003, bcdDevice= 1.00
[422070.330836] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[422070.330839] usb 1-2: Product: RP2 Boot
[422070.330842] usb 1-2: Manufacturer: Raspberry Pi
[422070.330845] usb 1-2: SerialNumber: E0C912D24340
[422070.415044] usb-storage 1-2:1.0: USB Mass Storage device detected
[422070.415349] scsi host2: usb-storage 1-2:1.0
[422070.415538] usbcore: registered new interface driver usb-storage
[422070.418743] usbcore: registered new interface driver uas
[422071.551633] usb 1-2: reset full-speed USB device number 16 using xhci_hcd
[422071.727779] scsi 2:0:0:0: Direct-Access     RPI      RP2              1    PQ: 0 ANSI: 2
[422071.728263] sd 2:0:0:0: Attached scsi generic sg2 type 0
[422071.728572] sd 2:0:0:0: [sdc] 262144 512-byte logical blocks: (134 MB/128 MiB)
[422071.729857] sd 2:0:0:0: [sdc] Write Protect is off
[422071.729860] sd 2:0:0:0: [sdc] Mode Sense: 03 00 00 00
[422071.731895] sd 2:0:0:0: [sdc] No Caching mode page found
[422071.731900] sd 2:0:0:0: [sdc] Assuming drive cache: write through
[422071.767149]  sdc: sdc1
[422071.771908] sd 2:0:0:0: [sdc] Attached SCSI removable disk

[422070.155550] usb 1-2: new full-speed USB device number 16 using xhci_hcd

[422070.330829] usb 1-2: New USB device found, idVendor=2e8a, idProduct=0003, bcdDevice= 1.00

[422070.330836] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3

[422070.330839] usb 1-2: Product: RP2 Boot

[422070.330842] usb 1-2: Manufacturer: Raspberry Pi

[422070.330845] usb 1-2: SerialNumber: E0C912D24340

[422070.415044] usb-storage 1-2:1.0: USB Mass Storage device detected

[422070.415349] scsi host2: usb-storage 1-2:1.0

[422070.415538] usbcore: registered new interface driver usb-storage

[422070.418743] usbcore: registered new interface driver uas

[422071.551633] usb 1-2: reset full-speed USB device number 16 using xhci_hcd

[422071.727779] scsi 2:0:0:0: Direct-Access RPI RP2 1 PQ: 0 ANSI: 2

[422071.728263] sd 2:0:0:0: Attached scsi generic sg2 type 0

[422071.728572] sd 2:0:0:0: [sdc] 262144 512-byte logical blocks: (134 MB/128 MiB)

[422071.729857] sd 2:0:0:0: [sdc] Write Protect is off

[422071.729860] sd 2:0:0:0: [sdc] Mode Sense: 03 00 00 00

[422071.731895] sd 2:0:0:0: [sdc] No Caching mode page found

[422071.731900] sd 2:0:0:0: [sdc] Assuming drive cache: write through

[422071.767149] sdc: sdc1

[422071.771908] sd 2:0:0:0: [sdc] Attached SCSI removable disk

为RPI-RP2大容量存储设备安装设备。

将pico_micropython_20210121.uf2文件复制到驱动器后，它会自动卸载且作为串行设备重新启动：

[422425.812363] usb 1-2: new full-speed USB device number 19 using xhci_hcd
[422425.990450] usb 1-2: New USB device found, idVendor=2e8a, idProduct=0005, bcdDevice= 1.00
[422425.990459] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[422425.990463] usb 1-2: Product: Board in FS mode
[422425.990466] usb 1-2: Manufacturer: MicroPython
[422425.990470] usb 1-2: SerialNumber: 000000000000
[422426.016529] cdc_acm 1-2:1.0: ttyACM0: USB ACM device

[422425.812363] usb 1-2: new full-speed USB device number 19 using xhci_hcd

[422425.990450] usb 1-2: New USB device found, idVendor=2e8a, idProduct=0005, bcdDevice= 1.00

[422425.990459] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3

[422425.990463] usb 1-2: Product: Board in FS mode

[422425.990466] usb 1-2: Manufacturer: MicroPython

[422425.990470] usb 1-2: SerialNumber: 000000000000

[422426.016529] cdc_acm 1-2:1.0: ttyACM0: USB ACM device

在这一点上，树莓派网站上的入门指南不是很有用，我们只好切换到Python SDK文档（PDF）。

该文档使用minicom进行串行控制台，但鉴于Bootterm更容易使用故我更中意它。无论您在何种情况下进行 Linux 编程，请确保当前用户已添加到dialout组，否则您需要将所有程序作为root用户身份运行：

sudo usermod -a -G dialout $(whoami)

1	sudo usermod -a -G dialout $(whoami)

Bootterm正确检测到ttyACM0端口，所以我只运行”bt”来访问MicroPython REPL接口，并键入一些MicroPython命令。

$ bt -l
 port |  age (sec) | device     | driver           | description          
------+------------+------------+------------------+----------------------
 *  0 |         29 | ttyACM0    | cdc_acm          | Board CDC        
 
$ bt
No port specified, using ttyACM0 (last registered). Use -l to list ports.
Trying port ttyACM0... Connected to ttyACM0 at 115200 bps.
Escape character is 'Ctrl-]'. Use escape followed by '?' for help.
 
>>> print("Hello, Pico!")
Hello, Pico!
>>> from machine import Pin
>>> led = Pin(25, Pin.OUT)
>>> led.value(1)
>>> led2 = Pin(15, Pin.OUT)
>>> led2.value(1)
>>>

$ bt -l

port | age (sec) | device | driver | description

------+------------+------------+------------------+----------------------

* 0 | 29 | ttyACM0 | cdc_acm | Board CDC

$ bt

No port specified, using ttyACM0 (last registered). Use -l to list ports.

Trying port ttyACM0... Connected to ttyACM0 at 115200 bps.

Escape character is 'Ctrl-]'. Use escape followed by '?' for help.

>>> print("Hello, Pico!")

Hello, Pico!

>>> from machine import Pin

>>> led = Pin(25, Pin.OUT)

>>> led.value(1)

>>> led2 = Pin(15, Pin.OUT)

>>> led2.value(1)

>>>

我可以打开板载 LED （GP25），但当我为面包板上的 LED （GP15）执行相同操作时，它不起作用。我重新检查了电路，并使用万用表检查电压，发现GP25仍然拉低。网络搜索显示GP15在电路Python中被禁用，源于它会干扰USB接口。

GP15由内部USB外围设备使用，不应故意使用它

MicroPython也是如此，所以我切换到相邻的引脚（GP14，引脚19）：

>>> led2 = Pin(14, Pin.OUT)
>>> led2.value(1)

1 2	>>> led2 = Pin(14, Pin.OUT) >>> led2.value(1)

果然，成功了！如果您想了解有关MicroPython API 的更多信息，请按 Ctrl+B 并输入帮助（）：

>>> 
raw REPL; CTRL-B to exit
>
MicroPython v1.13-290-g556ae7914 on 2021-01-21; Raspberry Pi Pico with RP2040
Type "help()" for more information.
>>> help()
Welcome to MicroPython!
 
For online help please visit https://micropython.org/help/.
 
For access to the hardware use the 'machine' module.  RP2 specific commands
are in the 'rp2' module.
 
Quick overview of some objects:
  machine.Pin(pin) -- get a pin, eg machine.Pin(0)
  machine.Pin(pin, m, [p]) -- get a pin and configure it for IO mode m, pull mode p
    methods: init(..), value([v]), high(), low(), irq(handler)
  machine.ADC(pin) -- make an analog object from a pin
    methods: read_u16()
  machine.PWM(pin) -- make a PWM object from a pin
    methods: deinit(), freq([f]), duty_u16([d]), duty_ns([d])
  machine.I2C(id) -- create an I2C object (id=0,1)
    methods: readfrom(addr, buf, stop=True), writeto(addr, buf, stop=True)
             readfrom_mem(addr, memaddr, arg), writeto_mem(addr, memaddr, arg)
  machine.SPI(id, baudrate=1000000) -- create an SPI object (id=0,1)
    methods: read(nbytes, write=0x00), write(buf), write_readinto(wr_buf, rd_buf)
  machine.Timer(freq, callback) -- create a software timer object
    eg: machine.Timer(freq=1, callback=lambda t:print(t))
 
Pins are numbered 0-29, and 26-29 have ADC capabilities
Pin IO modes are: Pin.IN, Pin.OUT, Pin.ALT
Pin pull modes are: Pin.PULL_UP, Pin.PULL_DOWN
 
Useful control commands:
  CTRL-C -- interrupt a running program
  CTRL-D -- on a blank line, do a soft reset of the board
  CTRL-E -- on a blank line, enter paste mode
 
For further help on a specific object, type help(obj)
For a list of available modules, type help('modules')

>>>

raw REPL; CTRL-B to exit

MicroPython v1.13-290-g556ae7914 on 2021-01-21; Raspberry Pi Pico with RP2040

Type "help()" for more information.

>>> help()

Welcome to MicroPython!

For online help please visit https://micropython.org/help/.

For access to the hardware use the 'machine' module. RP2 specific commands

are in the 'rp2' module.

Quick overview of some objects:

machine.Pin(pin) -- get a pin, eg machine.Pin(0)

machine.Pin(pin, m, [p]) -- get a pin and configure it for IO mode m, pull mode p

methods: init(..), value([v]), high(), low(), irq(handler)

machine.ADC(pin) -- make an analog object from a pin

methods: read_u16()

machine.PWM(pin) -- make a PWM object from a pin

methods: deinit(), freq([f]), duty_u16([d]), duty_ns([d])

machine.I2C(id) -- create an I2C object (id=0,1)

methods: readfrom(addr, buf, stop=True), writeto(addr, buf, stop=True)

readfrom_mem(addr, memaddr, arg), writeto_mem(addr, memaddr, arg)

machine.SPI(id, baudrate=1000000) -- create an SPI object (id=0,1)

methods: read(nbytes, write=0x00), write(buf), write_readinto(wr_buf, rd_buf)

machine.Timer(freq, callback) -- create a software timer object

eg: machine.Timer(freq=1, callback=lambda t:print(t))

Pins are numbered 0-29, and 26-29 have ADC capabilities

Pin IO modes are: Pin.IN, Pin.OUT, Pin.ALT

Pin pull modes are: Pin.PULL_UP, Pin.PULL_DOWN

Useful control commands:

CTRL-C -- interrupt a running program

CTRL-D -- on a blank line, do a soft reset of the board

CTRL-E -- on a blank line, enter paste mode

For further help on a specific object, type help(obj)

For a list of available modules, type help('modules')

Ubuntu 20.04 确实有Thonny 3.2.7 在其存储库中，我们可以使用 sudo apt install thonny进行安装，但它不支持树莓派Pico，因此，我用pip3安装了最新版本的程序（v3.3.3）：我们可以用”Ctrl+”后面跟着”q”退出bootterm。但如果我们想在板上保存Python程序并自动运行呢？我在Python SDK文档中未见到任何关于这一点内容，所以我不得不跳到第三个指南，找到的最佳方法是使用Thonny。

pip3 install thonny

1	pip3 install thonny

然后，我进入Run->Select interpreter… 选择了“MicroPython (树莓派Pico)“.

选择MicroPython

从用户界面，我可以输入一些代码来关闭板载LED：

为了以一秒的间隔闪烁板载 LED 和面包板 LED，我复制并修改了 Python SDK 文档中的一些代码：

from machine import Pin, Timer
led = Pin(25, Pin.OUT)
led2 = Pin(14, Pin.OUT)
led.value(0)
led2.value(1)
tim = Timer()
def tick(timer):
 global led, led2
 led.toggle()
 led2.toggle()
 
tim.init(freq=1, mode=Timer.PERIODIC, callback=tick)

from machine import Pin, Timer

led = Pin(25, Pin.OUT)

led2 = Pin(14, Pin.OUT)

led.value(0)

led2.value(1)

tim = Timer()

def tick(timer):

global led, led2

led.toggle()

led2.toggle()

tim.init(freq=1, mode=Timer.PERIODIC, callback=tick)

我保存文件作为我的电脑上的blink.py，它运行正常。但是，如果您想在没有 PC 的情况下运行代码，则可以将其保存到树莓派Pico。点击File->Save copy，然后点击”树莓派Pico”按钮，

并将程序保存为main.py。现在，您可以通过将板连接到任何 USB 电源自动运行程序。

树莓派Pico上的 C/C++

让我们尝试一下”C/C++ SDK”，除了一些用 C++ 编写的工具外，基本上都是 C 语言。我们可以回到官方入门文档，在boot模式下，我们被要求将blink.uf2复制到树莓派Pico，它确实使板载 LED 闪烁。它的工作原理非常简单，因为二进制是预构建的，但我们真正想做的是修改源代码，并建立我们自己的二进制文件来使内部和外部 LED 闪烁。

因此，我们必须安装C/C++ SDK、依赖关系和示例，具体如下：

sudo apt install cmake gcc-arm-none-eabi libnewlib-arm-none-eabi build-essential
git clone https://github.com/raspberrypi/pico-sdk
cd pico-sdk
git submodule update --init
cd ..
git clone -b master https://github.com/raspberrypi/pico-examples.git

sudo apt install cmake gcc-arm-none-eabi libnewlib-arm-none-eabi build-essential

git clone https://github.com/raspberrypi/pico-sdk

cd pico-sdk

git submodule update --init

cd ..

git clone -b master https://github.com/raspberrypi/pico-examples.git

我们可以看看pico-examples/blink/blink.c的闪烁示例：

/**
 * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */
 
#include "pico/stdlib.h"
 
int main() {
    const uint LED_PIN = 25;
    gpio_init(LED_PIN);
    gpio_set_dir(LED_PIN, GPIO_OUT);
    while (true) {
        gpio_put(LED_PIN, 1);
        sleep_ms(250);
        gpio_put(LED_PIN, 0);
        sleep_ms(250);
    }
}

/**

* SPDX-License-Identifier: BSD-3-Clause

#include "pico/stdlib.h"

int main() {

const uint LED_PIN = 25;

gpio_init(LED_PIN);

gpio_set_dir(LED_PIN, GPIO_OUT);

while (true) {

gpio_put(LED_PIN, 1);

sleep_ms(250);

gpio_put(LED_PIN, 0);

sleep_ms(250);

}

在修改之前，我们应尝试先导出 SDK 路径并配置构建：

$ cd pico-examples/blink
$ export PICO_SDK_PATH=../../pico-sdk
$ cmake ..
Using PICO_SDK_PATH from environment ('../../pico-sdk')
Pico SDK is located at /home/jaufranc/edev/sandbox/pico-sdk
Defaulting PICO_PLATFORM to rp2040 since not specified.
Defaulting PICO platform compiler to pico_arm_gcc since not specified.
-- Defaulting build type to 'Release' since not specified.
PICO compiler is pico_arm_gcc
PICO_GCC_TRIPLE defaulted to arm-none-eabi
-- The C compiler identification is GNU 9.2.1
-- The CXX compiler identification is GNU 9.2.1
-- The ASM compiler identification is GNU
-- Found assembler: /usr/bin/arm-none-eabi-gcc
Defaulting PICO target board to pico since not specified.
Using board configuration from /home/jaufranc/edev/sandbox/pico-sdk/src/boards/include/boards/pico.h
-- Found Python3: /usr/bin/python3.8 (found version "3.8.5") found components: Interpreter 
TinyUSB available at /home/jaufranc/edev/sandbox/pico-sdk/lib/tinyusb/src/portable/raspberrypi/rp2040; adding USB support.
-- Could NOT find Doxygen (missing: DOXYGEN_EXECUTABLE) 
ELF2UF2 will need to be built
PIOASM will need to be built
-- Configuring done
-- Generating done
-- Build files have been written to: /home/jaufranc/edev/sandbox/pico-examples/blink

$ cd pico-examples/blink

$ export PICO_SDK_PATH=../../pico-sdk

$ cmake ..

Using PICO_SDK_PATH from environment ('../../pico-sdk')

Pico SDK is located at /home/jaufranc/edev/sandbox/pico-sdk

Defaulting PICO_PLATFORM to rp2040 since not specified.

Defaulting PICO platform compiler to pico_arm_gcc since not specified.

-- Defaulting build type to 'Release' since not specified.

PICO compiler is pico_arm_gcc

PICO_GCC_TRIPLE defaulted to arm-none-eabi

-- The C compiler identification is GNU 9.2.1

-- The CXX compiler identification is GNU 9.2.1

-- The ASM compiler identification is GNU

-- Found assembler: /usr/bin/arm-none-eabi-gcc

Defaulting PICO target board to pico since not specified.

Using board configuration from /home/jaufranc/edev/sandbox/pico-sdk/src/boards/include/boards/pico.h

-- Found Python3: /usr/bin/python3.8 (found version "3.8.5") found components: Interpreter

TinyUSB available at /home/jaufranc/edev/sandbox/pico-sdk/lib/tinyusb/src/portable/raspberrypi/rp2040; adding USB support.

-- Could NOT find Doxygen (missing: DOXYGEN_EXECUTABLE)

ELF2UF2 will need to be built

PIOASM will need to be built

-- Configuring done

-- Generating done

-- Build files have been written to: /home/jaufranc/edev/sandbox/pico-examples/blink

现在可以进入一个blink目录（一个新目录，由cmake生成），然后运行make：

$ cd blink
$ make -j8
Scanning dependencies of target ELF2UF2Build
Scanning dependencies of target bs2_default
[  0%] Creating directories for 'ELF2UF2Build'
[  0%] No download step for 'ELF2UF2Build'
[  0%] No patch step for 'ELF2UF2Build'
[  0%] No update step for 'ELF2UF2Build'
[  0%] Building ASM object pico_sdk/src/rp2_common/boot_stage2/CMakeFiles/bs2_default.dir/boot2_w25q080.S.obj
[  0%] Performing configure step for 'ELF2UF2Build'
[  0%] Linking ASM executable bs2_default.elf
[  0%] Built target bs2_default
...
[ 50%] Building CXX object blink/CMakeFiles/blink.dir/home/jaufranc/edev/sandbox/pico-sdk/src/rp2_common/pico_standard_link/new_delete.cpp.obj
[ 50%] Building C object blink/CMakeFiles/blink.dir/home/jaufranc/edev/sandbox/pico-sdk/src/rp2_common/pico_standard_link/binary_info.c.obj
[100%] Building C object blink/CMakeFiles/blink.dir/home/jaufranc/edev/sandbox/pico-sdk/src/rp2_common/pico_stdio/stdio.c.obj
[100%] Building C object blink/CMakeFiles/blink.dir/home/jaufranc/edev/sandbox/pico-sdk/src/rp2_common/pico_stdio_uart/stdio_uart.c.obj
[100%] Linking CXX executable blink.elf
[100%] Built target blink

$ cd blink

$ make -j8

Scanning dependencies of target ELF2UF2Build

Scanning dependencies of target bs2_default

[ 0%] Creating directories for 'ELF2UF2Build'

[ 0%] No download step for 'ELF2UF2Build'

[ 0%] No patch step for 'ELF2UF2Build'

[ 0%] No update step for 'ELF2UF2Build'

[ 0%] Building ASM object pico_sdk/src/rp2_common/boot_stage2/CMakeFiles/bs2_default.dir/boot2_w25q080.S.obj

[ 0%] Performing configure step for 'ELF2UF2Build'

[ 0%] Linking ASM executable bs2_default.elf

[ 0%] Built target bs2_default

...

[ 50%] Building CXX object blink/CMakeFiles/blink.dir/home/jaufranc/edev/sandbox/pico-sdk/src/rp2_common/pico_standard_link/new_delete.cpp.obj

[ 50%] Building C object blink/CMakeFiles/blink.dir/home/jaufranc/edev/sandbox/pico-sdk/src/rp2_common/pico_standard_link/binary_info.c.obj

[100%] Building C object blink/CMakeFiles/blink.dir/home/jaufranc/edev/sandbox/pico-sdk/src/rp2_common/pico_stdio/stdio.c.obj

[100%] Building C object blink/CMakeFiles/blink.dir/home/jaufranc/edev/sandbox/pico-sdk/src/rp2_common/pico_stdio_uart/stdio_uart.c.obj

[100%] Linking CXX executable blink.elf

[100%] Built target blink

现在有一堆文件：

jaufranc@cnx-laptop-4:~/edev/sandbox/pico-examples/blink/blink$ ls -l
total 636
-rwxrwxr-x 1 jaufranc jaufranc  12696 Jan 24 11:42 blink.bin
-rw-rw-r-- 1 jaufranc jaufranc 197019 Jan 24 11:42 blink.dis
-rwxrwxr-x 1 jaufranc jaufranc 204232 Jan 24 11:42 blink.elf
-rw-rw-r-- 1 jaufranc jaufranc 172574 Jan 24 11:42 blink.elf.map
-rw-rw-r-- 1 jaufranc jaufranc  35778 Jan 24 11:42 blink.hex
-rw-rw-r-- 1 jaufranc jaufranc  25600 Jan 24 11:42 blink.uf2
drwxrwxr-x 4 jaufranc jaufranc   4096 Jan 24 11:41 CMakeFiles
-rw-rw-r-- 1 jaufranc jaufranc   1004 Jan 24 11:39 cmake_install.cmake
drwxrwxr-x 4 jaufranc jaufranc   4096 Jan 24 11:39 elf2uf2
-rw-rw-r-- 1 jaufranc jaufranc  89141 Jan 24 11:39 Makefile

jaufranc@cnx-laptop-4:~/edev/sandbox/pico-examples/blink/blink$ ls -l

total 636

-rwxrwxr-x 1 jaufranc jaufranc 12696 Jan 24 11:42 blink.bin

-rw-rw-r-- 1 jaufranc jaufranc 197019 Jan 24 11:42 blink.dis

-rwxrwxr-x 1 jaufranc jaufranc 204232 Jan 24 11:42 blink.elf

-rw-rw-r-- 1 jaufranc jaufranc 172574 Jan 24 11:42 blink.elf.map

-rw-rw-r-- 1 jaufranc jaufranc 35778 Jan 24 11:42 blink.hex

-rw-rw-r-- 1 jaufranc jaufranc 25600 Jan 24 11:42 blink.uf2

drwxrwxr-x 4 jaufranc jaufranc 4096 Jan 24 11:41 CMakeFiles

-rw-rw-r-- 1 jaufranc jaufranc 1004 Jan 24 11:39 cmake_install.cmake

drwxrwxr-x 4 jaufranc jaufranc 4096 Jan 24 11:39 elf2uf2

-rw-rw-r-- 1 jaufranc jaufranc 89141 Jan 24 11:39 Makefile

最重要的是blink.uf2，我们可以复制到树莓派Pico运行程序，并闪烁.elf，可用于调试器（OpenOCD + GDB），但这是入门指南的范围。

现在，我们知道如何为Pico板编译 C 程序，让我们修改闪烁.c示例，或者打开和关闭连接到 PIN 14 的板载 LED 和外部 LED：

#include "pico/stdlib.h"
 
int main() {
    const uint LED_PIN = 25; /* onboard LED */
    const uint LED2_PIN = 14; /* external LED */
    gpio_init(LED_PIN);
    gpio_set_dir(LED_PIN, GPIO_OUT);
    gpio_init(LED2_PIN);
    gpio_set_dir(LED2_PIN, GPIO_OUT);
    while (true) {
        gpio_put(LED_PIN, 1);
        gpio_put(LED2_PIN, 0);
        sleep_ms(1000);
        gpio_put(LED_PIN, 0);
        gpio_put(LED2_PIN, 1);
        sleep_ms(1000);
    }
}

#include "pico/stdlib.h"

int main() {

const uint LED_PIN = 25; /* onboard LED */

const uint LED2_PIN = 14; /* external LED */

gpio_init(LED_PIN);

gpio_set_dir(LED_PIN, GPIO_OUT);

gpio_init(LED2_PIN);

gpio_set_dir(LED2_PIN, GPIO_OUT);

while (true) {

gpio_put(LED_PIN, 1);

gpio_put(LED2_PIN, 0);

sleep_ms(1000);

gpio_put(LED_PIN, 0);

gpio_put(LED2_PIN, 1);

sleep_ms(1000);

}

再次构建程序：

cd blink
make

1 2	cd blink make

进入boot模式并复制blink.uf2到板，成功了！

实践证明，可以通过 C 或 Python 程序实现相同的结果，另外，我们将在即将发布的帖子中查看 RP2040 的 PIO （可编程 IO）界面，因为 AFAICT 是树莓派 RP2040 与其他微控制器最大的区别所在。

最后，十分感谢Cytron寄了树莓派Pico给我进行评测。如果你所在的位置在东盟，那么就可以用 4.98 美元的价格购买到他们的板子。其他地区的话，可以用5美元购买到。现在，它已经在全球范围内出售了。

Nicholas Dong 董巷

文章翻译者：Nicholas，技术支持工程师、瑞科慧联（RAK）高级工程师，深耕嵌入式开发技术、物联网行业多年，拥有丰富的行业经验和新颖独到的眼光！

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