SPI 优化提升啦显示刷新的速率

A ["Discussions"](https://github.com/Bodmer/TFT_eSPI/discussions) facility has been added for Q&A etc. Use the ["Issues"](https://github.com/Bodmer/TFT_eSPI/issues) tab only for problems with the library. Thanks! # News 1. DMA can now be used with the Raspberry Pi Pico (RP2040) when used with both 8 bit parallel and 16 bit colour SPI displays. See "Bouncy_Circles" sketch. ["Bouncing circles"](https://www.youtube.com/watch?v=njFXIzCTQ_Q&lc=UgymaUIwOIuihvYh-Qt4AaABAg) 2. Support hase been added for the ESP32 S2 processor variant. A [new user setup](https://github.com/Bodmer/TFT_eSPI/blob/master/User_Setups/Setup70_ESP32_S2_ILI9341.h) file has been added as an example setup with an ILI9341 TFT. You will need to load ESP32 Arduino board package 2.0.0 or later to use the updated library with an ESP32. 3. The library now supports the Raspberry Pi Pico with both the [official Arduino board package](https://github.com/arduino/ArduinoCore-mbed) and the one provided by [Earle Philhower](https://github.com/earlephilhower/arduino-pico). The setup file "Setup60_RP2040_ILI9341.h" has been used for tests with an ILI9341 display. At the moment only SPI interface displays have been tested. SPI port 0 is the default but SPI port 1 can be specifed in the setup file if those SPI pins are used. ["Rotating cube demo"](https://www.youtube.com/watch?v=4fPxEN9ImVE) 4. Viewports can now be applied to sprites e.g. spr.setViewport(5, 5, 20, 20); so graphics can be restricted to a particular area of the sprite. This operates in the same way as the TFT viewports, see 5. below. 5. The library now provides a "viewport" capability. See "Viewport_Demo" and "Viewport_graphicstest" examples. When a viewport is defined graphics will only appear within that window. The coordinate datum by default moves to the top left corner of the viewport, but can optionally remain at top left corner of TFT. The GUIslice library will make use of this feature to speed up the rendering of GUI objects ([see #769](https://github.com/Bodmer/TFT_eSPI/issues/769)). 6. The library now supports SSD1963 based screen, this has been tested on a [480x800 screen](https://www.buydisplay.com/7-tft-screen-touch-lcd-display-module-w-ssd1963-controller-board-mcu) with an ESP32. The interface is 8 bit parallel only as that controller does not support a SPI interface. 7. A companion library [U8g2_for_TFT_eSPI](https://github.com/Bodmer/U8g2_for_TFT_eSPI) has been created to allow U8g2 library fonts to be used with TFT_eSPI. 8. The library now supports SPI DMA transfers for both ESP32 and STM32 processors. The DMA Test examples now work on the ESP32 for SPI displays (excluding RPi type and ILI9488). 9. A new option has been added for STM32 processors to optimise performance where Port A (or B) pins 0-7 are used for the 8 bit parallel interface data pins 0-7 to the TFT. This gives a dramatic 8 times better rendering performance for the lower clock rate STM32 processors such as the STM32F103 "Blue Pill" or STM411 "Black Pill" since no time consuming data bit manipulation is required. See setup file "User_Setups/Setup35_ILI9341_STM32_Port_Bus.h". # TFT_eSPI An Arduino IDE compatible graphics and fonts library for 32 bit processors. The library is targeted at 32 bit processors, it has been performance optimised for STM32, ESP8266 and ESP32 types. The library can be loaded using the Arduino IDE's Library Manager. Direct Memory Access (DMA) can be used with the ESP32, RP2040 and STM32 processors to improve rendering performance. Optimised drivers are incorporated for the following processors: * RP2040, e.g. Raspberry Pi Pico * ESP32 and ESP32-S2 (ESP32C3 untested) * ESP8266 * STM32F1xx, STM32F2xx, STM32F4xx, STM32F767 (higher RAM processors recommended) Generic (non-optimised Arduino function calls) are used by the library for other processors. "Four wire" SPI and 8 bit parallel interfaces are supported. Due to lack of GPIO pins the 8 bit parallel interface is NOT supported on the ESP8266. 8 bit parallel interface TFTs (e.g. UNO format mcufriend shields) can used with the STM32 Nucleo 64/144 range or the UNO format ESP32 (see below for ESP32). The RP2040 has not been tested with parallel displays. Displays using the following controllers are supported: * ILI9163 * ILI9225 * ILI9341 * ILI9481 * ILI9486 * ILI9488 (DMA not supported for this 18 bit display) * HX8357D * S6D02A1 * SSD1351 * SSD1963 * ST7735 * ST7789 * ST7796 * GC9A01 ILI9341 and ST7796 SPI based displays are recommended as starting point for experimenting with this library. The library supports some TFT displays designed for the Raspberry Pi (RPi) that are based on a ILI9486 or ST7796 driver chip with a 480 x 320 pixel screen. The ILI9486 RPi display must be of the Waveshare design and use a 16 bit serial interface based on the 74HC04, 74HC4040 and 2 x 74HC4094 logic chips. Note that due to design variations between these displays not all RPi displays will work with this library, so purchasing a RPi display of these types solely for use with this library is not recommended. The "good" RPi displays are the [MHS-4.0 inch Display-B type ST7796](http://www.lcdwiki.com/MHS-4.0inch_Display-B) and [Waveshare 3.5 inch ILI9486 Type C](https://www.waveshare.com/wiki/3.5inch_RPi_LCD_(C)) displays are supported and provides good performance. These have a dedicated controller and can be clocked at up to 80MHz with the ESP32 (55MHz with STM32 and 40MHz with ESP8266). Some displays permit the internal TFT screen RAM to be read, some of the examples use this feature. The TFT_Screen_Capture example allows full screens to be captured and sent to a PC, this is handy to create program documentation. The library supports Waveshare 2 and 3 colour ePaper displays using full frame buffers. This addition is relatively immature and thus only one example has been provided. The library includes a "Sprite" class, this enables flicker free updates of complex graphics. Direct writes to the TFT with graphics functions are still available, so existing sketches do not need to be changed. # Sprites A Sprite is notionally an invisible graphics screen that is kept in the processors RAM. Graphics can be drawn into the Sprite just as they can be drawn directly to the screen. Once the Sprite is completed it can be plotted onto the screen in any position. If there is sufficient RAM then the Sprite can be the same size as the screen and used as a frame buffer. Sprites by default use 16 bit colours, the bit depth can be set to 8 bits (256 colours) , or 1 bit (any 2 colours) to reduce the RAM needed. On an ESP8266 the largest 16 bit colour Sprite that can be created is about 160x128 pixels, this consumes 40Kbytes of RAM. On an ESP32 the workspace RAM is more limited than the datasheet implies so a 16 bit colour Sprite is limited to about 200x200 pixels (~80Kbytes), an 8 bit sprite to 320x240 pixels (~76kbytes). A 1 bit per pixel Sprite requires only 9600 bytes for a full 320 x 240 screen buffer, this is ideal for supporting use with 2 colour bitmap fonts. One or more sprites can be created, a sprite can be any pixel width and height, limited only by available RAM. The RAM needed for a 16 bit colour depth Sprite is (2 x width x height) bytes, for a Sprite with 8 bit colour depth the RAM needed is (width x height) bytes. Sprites can be created and deleted dynamically as needed in the sketch, this means RAM can be freed up after the Sprite has been plotted on the screen, more RAM intensive WiFi based code can then be run and normal graphics operations still work. Drawing graphics into a sprite is very fast, for those familiar with the Adafruit "graphicstest" example, this whole test completes in 18ms in a 160x128 sprite. Examples of sprite use can be found in the "examples/Sprite" folder. Sprites can be plotted to the TFT with one colour being specified as "transparent", see Transparent_Sprite_Demo example. If an ESP32 board has SPIRAM (i.e. PSRAM) fitted then Sprites