我应该买正点原子哪块STM32板子好？

建议购买STM32F103系列的，上手快些。

    STM32F103系列只是比STM32F407系列运算速度慢，资源少点（例如STM32F407支持6个串口，但是STM32F103只支持5个口串口），
    STM32F103系列晶振为72M，STM32F407系列晶振为168M.

    STM32F407还支持硬件浮点数，所以计算浮点数时会大幅提高速度，其它没有什么区别。

     1、下面是STM32F103VC的系统的硬件资源

                  ARM 32-bit Cortex-M3 Microcontroller, 72MHz, 256kB Flash, 48kB SRAM,
                 Flexible Static Memory Controller for SRAM, PSRAM, NOR and NAND Flash,
                PLL, Embedded Internal RC 8MHz and 32kHz, Real-Time Clock,
               Nested Interrupt Controller, Power Saving Modes, JTAG and SWD,
                 4 Synch. 16-bit Timers with Input Capture, Output Compare and PWM,
                  2 16-bit Advanced Timer, 2 16-bit Basic Timer, 2 16-bit Watchdog Timers,
                   SysTick Timer, 3 SPI/I2S, 2 I2C, 5 USART, USB 2.0 Full Speed Interface,
                 CAN 2.0B Active, 3 12-bit 16-ch A/D Converter, 2 12-bit D/A Converter,
                    SDIO, Fast I/O Ports

    2、下面是STM32F407IG的系统的硬件资源

Core
– ARM 32-bit Cortex-M4 CPU with FPU
– Adaptive real-time accelerator (ART Accelerator)
– 168 MHz maximum frequency, 210 DMIPS/1.25 DMIPS/MHz
– Memory protection unit
Memories
– Up to 1 Mbyte of Flash memory
– Up to 192+4 Kbytes of SRAM
– Flexible static memory controller
   (supports Compact Flash, SRAM, PSRAM, NOR, NAND memories)
LCD parallel interface, 8080/6800 modes
Clock, reset and supply management
– 1.7 V to 3.6 V application supply and I/Os
– POR, PDR, PVD and BOR
– 4 to 25 MHz crystal oscillator
– Internal 16 MHz factory-trimmed RC
– 32 kHz oscillator for RTC with calibration
– Internal 32 kHz RC with calibration
Low power
– Sleep, Stop, Standby modes
– VBAT supply for RTC,
   20×32 bit backup registers + optional 4 KB backup SRAM
3 x 12-bit, 0.41 us A/D converters
– up to 24 channels
2 x 12-bit D/A converters
General-purpose DMA
– 16-stream DMA controller with centralized FIFOs and burst support
Up to 17 timers
– up to 12 16-bit and 2 32-bit timers up to 150 MHz
Debug mode
– Serial wire debug (SWD) & JTAG
– Cortex-M4 Embedded Trace Macrocell
Up to 140 I/O ports with interrupt capability
– Up to 136 fast I/Os up to 60 MHz
– Up to 138 5 V-tolerant I/Os
Up to 15 communication interfaces
– Up to 3 x I2C interfaces
– Up to 4 USARTs/2 UARTs (10.5 Mbit/s, ISO 7816, LIN, IrDA, modem control)
– Up to 3 SPIs (37.5 Mbits/s)
– 2 x CAN interfaces (2.0B Active)
– SDIO interface
Advanced connectivity
– USB 2.0 FS device/host/OTG controller with on-chip PHY
– USB 2.0 HS/FS device/host/OTG controller with dedicated DMA,
   on-chip FS PHY and ULPI
– 10/100 Ethernet MAC with dedicated DMA
8 to 14-bit parallel camera interface up to 67.2 Mbytes/s
Cryptographic acceleration
– Hardware acceleration for AES 128, 192, 256, Triple DES, HASH (MD5, SHA-1)
Analog true random number generator
CRC calculation unit, 96-bit unique ID
RTC: subsecond accuracy, hardware calendar

现在准备买407了