寻找MCU参考

大家好，


我在STM32F4外设方面有很好的经验，但我是ST 8位系列的新手，所以我希望您的反馈和帮助能够以更低的成本匹配好的MCU，并且可以匹配这些功能：
- 3.3V操作
- 高速或中速的USB数据传输（成本优先），大容量存储声明（也是新的）以及USB的固件闪存功能：是否有任何我可以为此目的开始的库/示例？
- 带有DMA的SPI上的2个外设：1x用于外设读操作（20 MHz），1个用于 SDr/ w：以连续最小112 Kb / s写入且可靠，但896 Kb / s能够完美。我打算用Fats fs库来做。也许我需要2个DMA呢？
由于RAM的使用，这一点至关重要......我只是不知道它是否可能在8位MCU上......实际上我只需要在SPI上读取数据，将其保存在某处（最大2Gb）。在另一种模式下，通过USB将数据传输到PC。
- 1x i2c，400 kHz（中断模式或DMA + int）。
- 待机模式，低功耗（超低优先但不严格）。
- 1x 16位定时器，一些EXtiO ......
- 几个eeprom ......

您如何看待这一要求？ 8位系列有可能吗？

提前感谢您的回答
＃USB-SD-SPI-DMA



以下为原文




Hi all,


I had good experiences on STM32F4 peripherals, but I'm new to ST 8 bits family, so I'd like your feedback and help to match a good MCU at lower cost possible, and that could match that features :
- 3.3V operations
- USB data transfer at High or moderate speed (cost first), with a mass storage declaration (new to that too), and with firmware flashing capability by USB : is there any library/example I can start with for that purpose ?
- 2 peripherals on SPI with DMA : 1x for a peripheral read operation (20 MHz capable), and one for �SD r/w : write at continuous minimum 112 Kb/s with reliability, but 896 Kb/s capable would be perfect. I planned to do it with Fats fs library. Perhaps I will need 2 DMA for that ?
That point is critical because of the RAM usage... I just don't know if it's possible on an 8 bits MCU... In fact I just need to read datas on SPI, save it somewhere (with 2Gb  max)... And in another mode, transfer that datas to PC via USB.
- 1x i2c at 400 kHz (interrupt mode or DMA+int).
- Standby mode with low power (ultra low prefered but not critical).
- 1x 16 bits Timer, a few EXTIO...
- a few eeprom...

What do you think about this requirements ? Is it possible with 8 bits family ?

Thanks in advance for your answers  
#u***-sd-spi-dma