常用
//RS232使用MAX232 “负逻辑”的电压约定,用0v的TTL低电平把转成3~15V,5V的TTL高电平转成 -15 ~ -3v,不是差分信号,可达15米,2MHZ;
RS485是差分信号+地线共3根,可以达到1200米,50Mhz
//作为中断使用的GPIO,需要确认GPIO是否支持中断,避免使用不支持中断的GPIO
//一般,一片cmos电路最多可以同时接8个负载芯片
//isp要求单片机有驻留专门的程序,用以与上位机通信,接收固件数据并烧录到自身的ROM中,所以需要具备基本的最小系统电路(时钟和复位);
icp可以理解为MCU就是一块可供外部读写的存储芯片,不需要预置任何程序,不需要具备单片机可以运行的状态.
51单片机
Cortex-M核 +RTOS开发
//野火F407开发板的DAP仿真器配置：
//Keil 中1个汉字是双字节，删除需要按2次，如下操作可以解决：
其他
//四路带线USB串口控制继电器模块用法:
淘宝的使用CH340 的通过usb来控制 继电器的串口命令:
a00100a1
a00101a2
a00201a3
a00200a2
a00301a4
a00300a3
RT-Thread
//英飞凌XMC7100的msh的打印:
msh >help
RT-Thread shell commands:
reboot - Reboot System
pin - pin [option]
list - list objects
version - show RT-Thread version information
clear - clear the terminal screen
free - Show the memory usage in the system
ps - List threads in the system
help - RT-Thread shell help
backtrace - print backtrace of a thread
msh >ps
thread pri status sp stack size max used left tick error tcb addr usage
-------- --- ------- ---------- ---------- ------ ---------- ------- ---------- -----
tshell 20 running 0x000000b4 0x00001000 09% 0x00000009 OK 0x28006cc0 N/A
tidle0 31 ready 0x0000006c 0x00000100 42% 0x00000005 OK 0x28005754 N/A
timer 4 suspend 0x0000009c 0x00000200 30% 0x00000009 EINTRPT 0x28005b4c N/A
main 10 suspend 0x000000ac 0x00000800 10% 0x00000012 EINTRPT 0x280061e0 N/A
msh >pin
pin [option] GPIO
num: get pin number from hardware pin
mode: set pin mode to output/input/input_pullup/input_pulldown/output_od
e.g. MSH >pin mode GPIO output
read: read pin level of hardware pin
e.g. MSH >pin read GPIO
write: write pin level(high/low or on/off) to hardware pin
e.g. MSH >pin write GPIO high
help: this help list
GPIO e.g.:pin: command failed -88.
msh >list
Usage: list [options]
[options]:
thread - list threads
timer - list timers
sem - list semaphores
event - list events
mutex - list mutexs
mailbox - list mailboxs
msgqueue - list message queues
mempool - list memory pools
device - list devices
msh >version
\ | /
- RT - Thread Operating System
/ | \ 5.2.2 build Oct 18 2025 14:03:18
2006 - 2024 Copyright by RT-Thread team
msh >free
total : 758192
used : 8088
maximum : 8088
available: 750104
msh >list thread
thread pri status sp stack size max used left tick error tcb addr usage
-------- --- ------- ---------- ---------- ------ ---------- ------- ---------- -----
tshell 20 running 0x000000b4 0x00001000 09% 0x00000003 OK 0x28006cc0 N/A
tidle0 31 ready 0x0000006c 0x00000100 42% 0x00000017 OK 0x28005754 N/A
timer 4 suspend 0x0000009c 0x00000200 30% 0x00000009 EINTRPT 0x28005b4c N/A
main 10 suspend 0x000000ac 0x00000800 10% 0x00000012 EINTRPT 0x280061e0 N/A
msh >list timer
timer periodic timeout activated mode
-------- ---------- ---------- ----------- ---------
tshell 0x00000000 0x00000000 deactivated one shot
tidle0 0x00000000 0x00000000 deactivated one shot
timer 0x00000000 0x00000000 deactivated one shot
main 0x000003e8 0x0003018b activated one shot
current tick:0x0002ffa2
msh >list sem
semaphor v suspend thread
-------- --- --------------
shrx 001 0
stimer 000 1:timer
msh >list mutex
mutex owner hold priority suspend thread
-------- -------- ---- -------- --------------
heap (null) 0000 255 0000
msh >list mailbox
mailbox entry size suspend thread
-------- ---- ---- --------------
msh >list device
device type ref count
-------- -------------------- ----------
uart4 Character Device 2
uart2 Character Device 0
pin Pin Device 0
msh >
//Q: pkgs--update 和pkgs--upgrade 有什么区别呢?
A:
一个更新目录，一个更新具体package内容
前者更新当前项目引用的包到项目下的packages文件夹，后者更新本机的env文件夹下的软件包列表，它决定你的env菜单会出现哪些菜单项
update会下载包的源码，upgrade会下载包含包下载地址的json文件到env目录下的packages文件夹里，不会下载源码文件
//env加入windows的文件管理器菜单:
//board/kconfig的修改后的menuconfig:
