ST7735 LCD Controller driver（ST7735液晶显示控制器驱动程序）
Overview（概览）
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The ST7735S is a single-chip controller/driver for 262K-color, graphic type TFT-LCD. It consists of 396 source line and 162 gate line driving circuits. This chip is capable of connecting directly to an external microprocessor, and accepts Serial Peripheral Interface (SPI), 8-bit/9-bit/16-bit/18-bit parallel interface. Display data can be stored in the on-chip display data RAM of 132 x 162 x 18 bits. It can perform display data RAM read/write operation with no external operation clock to minimize power consumption. In addition, because of the integrated power supply circuits necessary to drive liquid crystal, it is possible to make a display system with fewer components.
The ST7735 LCD controller driver is a platform-agnostic driver, based on the generic MIPI driver. It implements display initialization, supports display rotation and implements the display flush callback. The user needs to implement only two platform-specific functions to send a command or pixel data to the controller via SPI or parallel bus. Typically these are implemented by calling the appropriate SDK library functions on the given platform.
ST7735S 是一款用于262K色彩、图形类型TFT-LCD的单芯片控制器/驱动器。它包含396个源码线和162个网线驱动电路。该芯片可以直接连接到外部微处理器，并接受串行外围接口（SPI）、8位/9位/16位/18位并行接口。显示数据可以存储在132 x 162 x 18位的芯片内显示数据RAM中。 它可以在没有外部操作时钟的情况下执行显示数据RAM读写操作，以最小化功耗。此外，由于集成了驱动液晶所需的电源电路，可以使用更少的元件构建显示系统。
ST7735 LCD控制器 driver is a platform-agnostic driver, based on the generic MIPI driver 是一个与平台无关的驱动程序，基于通用的MIPI驱动程序。它实现了显示初始化，支持显示旋转，并实现了显示刷新回调函数。用户只需要实现两个特定于平台的函数，通过SPI或并行总线向控制器发送命令或像素数据。通常，这些函数通过调用给定平台上适当的SDK库函数来实现。
Prerequisites（先决条件）
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There are no prerequisites.
没有先决条件。
Configuring the driver（配置驱动程序）
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Enable the ST7735 driver support in lv_conf.h, by cmake compiler define or by KConfig
#define LV_USE_ST7735 1
在lv_conf.h文件中启用ST7735驱动器支持，可以通过CMake编译器定义或通过KConfig来实现。
#define LV_USE_ST7735 1
Usage（用法）
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You need to implement two platform-dependent functions:
/* Send short command to the LCD. This function shall wait until the transaction finishes. */
int32_t my_lcd_send_cmd(lv_display_t *disp, const uint8_t *cmd, size_t cmd_size, const uint8_t *param, size_t param_size)
{
...
}
/* Send large array of pixel data to the LCD. If necessary, this function has to do the byte-swapping. This function can do the transfer in the background. */
int32_t my_lcd_send_color(lv_display_t *disp, const uint8_t *cmd, size_t cmd_size, uint8_t *param, size_t param_size)
{
...
}
To create an ST7735-based display use the function
/**
* Create an LCD display with ST7735 driver
* @param hor_res horizontal resolution
* @param ver_res vertical resolution
* @param flags default configuration settings (mirror, RGB ordering, etc.)
* @param send_cmd platform-dependent function to send a command to the LCD controller (usually uses polling transfer)
* @param send_color platform-dependent function to send pixel data to the LCD controller (usually uses DMA transfer: must implement a 'ready' callback)
* @return pointer to the created display
*/
lv_display_t * lv_st7735_create(uint32_t hor_res, uint32_t ver_res, lv_lcd_flag_t flags,
lv_st7735_send_cmd_cb_t send_cmd_cb, lv_st7735_send_color_cb_t send_color_cb);
For additional details and a working example see the generic MIPI driver documentation.
您需要实现两个平台相关的函数：
/* 将短命令发送给LCD，此函数将等待事务完成。 */
int32_t my_lcd_send_cmd(lv_display_t *disp, const uint8_t *cmd, size_t cmd_size, const uint8_t *param, size_t param_size)
{
...
}
/* 将大批量像素数据发送给LCD。必要时，此函数必须进行字节交换。此函数可以在后台进行传输。 */
int32_t my_lcd_send_color(lv_display_t *disp, const uint8_t *cmd, size_t cmd_size, uint8_t *param, size_t param_size)
{
...
}
要创建基于ST7735驱动器的显示，请使用以下函数：
/**
* 创建一个带有ST7735驱动器的LCD显示器
* @param hor_res 水平分辨率
* @param ver_res 垂直分辨率
* @param flags 默认配置设置（镜像，RGB顺序等）
* @param send_cmd 平台相关函数，用于向LCD控制器发送命令（通常使用轮询传输）
* @param send_color 平台相关函数，用于向LCD控制器发送像素数据（通常使用DMA传输：必须实现'准备好'回调函数）
* @return 指向创建的显示器的指针
*/
lv_display_t * lv_st7735_create(uint32_t hor_res, uint32_t ver_res, lv_lcd_flag_t flags,
lv_st7735_send_cmd_cb_t send_cmd_cb, lv_st7735_send_color_cb_t send_color_cb);
有关详细信息和工作示例，请查看`通用MIPI驱动程序文档 https://github.com/lvgl/lvgl/doc/integration/drivers/display/gen_mipi.rst。