Boris Vinogradov

It looks as real solution for me. I talk about current PR with @Disasm, he says: we can create clear path for migrate from old `nb api` to new `async...

Create first PR with little cosmetic changes #57

Add PLL Q configuration for usb #59

@mvertescher could You review #59 and #60? - first unblock me for adding other mcu blocks support (usb, sdio, sai and rnd depends on 48 MHz clock source), second provide...

@mvertescher I rewrite RCC configuration #74: to work version with highly compatible to previous version, so It add configuration for configure USB clock with or without use PLL for system...

It makes library clear: you can extend and update fat fs crate without hw depends and you can improve hw support without changes in fat fs. So crate is staied...

@fventuri thank you for detail instruction, it looks as error on cubicsdr side: ``` 2023-06-14 10:48:23.809969+0200 0x621d4 Default 0x0 19941 0 sdrplay_apiService: [0x16dd3b000]: devIdx0: sdrplay_apiService_rsp: checkTunerParamLimits: ERROR: Tuner1: rfFreq rfHz...

@fventuri thank you, I already debug this issue, yes it was -1 but they use double and on some layer of drivers it converts to int and back. But in...

@usbalbin this PR looks outdated and there are more non-necessary stuff.

Looks good for begin. Also would be better to use https://github.com/stm32-rs/stm32f4xx-hal/tree/master/src/spi base methodology: Bidi + Uni direction exchange implementation for future use in some crates like displays, smart LEDs, etc..