Change Fonts size (more readable, but not increase code size)
Rework display spi driver:
use DMA for read, write
add blitBitmap functions
Use DMA for color fill
More correct SPI bus control
Move color definitions to nanovna.h
Some code optimization for speed and size (save about 3k bytes)
Change grid Y resolution to 10
Fix convert from float to int (fix some rounding errors on plot)
Disable unused HAL serial
Change battery icon
Change Fonts size (more readable, but not increase code size) Rework display spi driver: use DMA for read, write add blitBitmap functions Use DMA for color fill More correct SPI bus control Move color definitions to nanovna.h Some code optimization for speed and size (save about 3k bytes) Change grid Y resolution to 10 Fix convert from float to int (fix some rounding errors on plot) Disable unused HAL serial Change battery icon