汇总：TH1621 LCD开发资料（20240406）

# HT1621 7 segment LCD library Library for 7-segment lcds based on the HT1621 driver. Very often marked as PDC-6X1. <img src="extras/photo1.jpg" alt="photo" width="500"> Based on the bitbanging efforts by [anxzhu](https://github.com/anxzhu) (2016-2018). APIs rewritten in 2018 to follow the LiquidCrystal format by [valerio\new] (https://github.com/5N44P). Refactored. Removed dependency on any MCU hardware. Added SPI support and text support. By Viacheslav Balandin https://github.com/hedgehogV/HT1621-lcd ## APIs reference * `HT1621(pPinSet *pCs, pPinSet *pSck, pPinSet *pMosi, pPinSet *pBacklight)` Ctor. Starts the lcd with the pin assignment declared. The backlight pin is optional * `HT1621(pInterface *pSpi, pPinSet *pCs, pPinSet *pBacklight)` Starts the lcd with SPI interface. CS and backlight pins are optional. Tested with CPOL=LOW, EDGE=1 * `void clear()` Clears the display * `void backlightOn()` Turns on the backlight * `void backlightOff()` Turns off the backlight * `void batteryLevel(uint8_t percents)` Accepts values from 0 to 100. Bigger values will be treated as 100. Battery charge represented by the rectangles above the battery symbol. * `void print(const char *str)` Print string (up to 6 characters) Allowed characters: letters, digits, space, minus, underscore. Not allowed characters will be displayed as spaces. See characters appearance in `Internal functioning` chapter * `void print(int32_t num)` Prints a signed integer between -99999 and 999999. Larger and smaller values will be displayed as -99999 and 999999 * `void print(float num, int precision)` Prints a float with 0 to 3 decimals, based on the `precision` parameter. Default value is 3 * `void print(int32_t multiplied_float, uint32_t multiplier)` Prints number with dot. Use it instead float. Float type usage may slow down many systems * `void displayOff()` Turns off the display (doesn't turn off the backlight) * `void displayOn()` Turns the display back on after it has been disabled by `noDisplay()` ## API usage To start display you have to call one of Ctors with pointers to toggle_Gpio or SpiTx functions. You may need a function wrapper. Wrapper example: ```cpp // spi wrapper void SpiTx(uint8_t *ptr, uint8_t size) { HAL_SPI_Transmit(&hspi2, ptr, size, 2000); } // cs wrapper void toggle_CS(bool b) { HAL_GPIO_WritePin(CS_GPIO_Port, CS_Pin, b? GPIO_PIN_SET:GPIO_PIN_RESET); } // ctor call example HT1621 lcd = HT1621(&SpiTx, &toggle_CS); // prints "hello" on display lcd.print("HELLO"); ``` ## Internal functioning Letters example. Source: https://www.dcode.fr/7-segment-display Some of them looks a bit strange. But 7-segment display isn't the best thing to show letters <img src="extras/letters.png" alt="photo" width="500"> ° -> 0x33 = 10 + 20 + 01 + 02 C -> 0x1D = 10 + 01 + 04 + 08 ``` ___10___ | | 01 20 |___02___| | | 04 40 |___08___| ```