【AT-START-F425 Review】No.07 8x8 Dual Color Dot Matrix Screen Carousel

韵湖葱白

【AT-START-F425 Review】No.07 8x8 Dual Color Dot Matrix Screen Carousel [Copy link]

 

## Introduction Since I tinkered with SLCD last time, I found that tinkering with hardware is not that complicated. The most important thing is that I can make a board for free (I really discovered a new world). This time I tinkered with a two-color 8X8 dot matrix screen, which was packaged and sent to me by a netizen from eeworld at a low price. I found a picture on the Internet, which looks like this:  ## About the two-color dot matrix specification (for reference):  Its corresponding schematic diagram is as follows:  Schematic diagram description: - 1,2,3,4,21,22,23,24 These 8 pins control the rows. - 5,6,7,8,9,10,11,12 These 8 pins control the green lights of the columns. - 13,14,15,16,17,18,19,20 These 8 pins control the red light of the column. ## Schematic design Generally, 74HC595 is needed to drive this kind of segment code LED. I spent a few dollars to buy 20 pieces of TM74HC595, which is produced by Tianwei.  You can refer to the chip manual for the details of this chip. Its basic function is serial to parallel conversion. Specific to our needs, since the two-color dot matrix shares 24 data, 3 pieces of TM74HC595 are required. As for how to connect, when we understand the principle of serial to parallel conversion, then three parallel, two parallel and one string, two strings and one parallel or three strings are all possible. The difference is the difference in external interface and program processing. Here we use the conventional two strings and one parallel, the two strings correspond to the column data, and the one parallel corresponds to the row data. The schematic diagram is as follows:   The corresponding board is as follows:  ## Program design## 74HC595 driver``` //#define LED_USING_SPI #if defined(SPI1_FOR_LED) /* SPI1:PB13-SCK-SPI_SCK PB14-CE-SPI_MISO PB15-DATA-SPI_MOSI */ #define CURRENT_SPI SPI1 #define CURRENT_SPI_RCU RCU_SPI1 #define LED_RCU CRM_GPIOB_PERIPH_CLOCK #define LED_GPIO GPIOB #define LED_CTRL_SCK GPIO_PINS_3 #define LED_CTRL_RCK GPIO_PINS_4 #define LED_CTRL_SI GPIO_PINS_5 #define LED_DATA_SCK GPIO_PINS_13 #define LED_DATA_RCK GPIO_PINS_14 #define LED_DATA_SI GPIO_PINS_15 #define ROW_OFF_ALL 0x00 #define ROW_ON(row) (0x80>>row) #ifdef LED_USING_SPI #else #define LED_CTRL_SCK_HIGH gpio_bits_set(LED_GPIO, LED_CTRL_SCK); #define LED_CTRL_SCK_LOW gpio_bits_reset(LED_GPIO, LED_CTRL_SCK); #define LED_CTRL_RCK_HIGH gpio_bits_set(LED_GPIO, LED_CTRL_RCK); #define LED_CTRL_RCK_LOW gpio_bits_reset(LED_GPIO, LED_CTRL_RCK); #define LED_CTRL_SI_HIGH gpio_ bits_set(LED_GPIO, LED_CTRL_SI); #define LED_CTRL_SI_LOW gpio_bits_reset(LED_GPIO, LED_CTRL_SI); #define LED_DATA_SCK_HIGH gpio_bits_set(LED_GPIO, LED_DATA_SCK); #define LED_DATA_SCK_LOW gpio_bits_reset(LED_GPIO, LED_DATA_SCK ); #define LED_DATA_RCK_HIGH gpio_bits_set(LED_GPIO, LED_DATA_RCK); #define LED_DATA_RCK_LOW gpio_bits_reset(LED_GPIO, LED_DATA_RCK); #define LED_DATA_SI_HIGH gpio_bits_set(LED_GPIO, LED_DATA_SI); #define LED_DATA_SI_LOW gpio_bits_reset(LED_GPIO, LED_ DATA_SI); #endif void spi5_init(){} #ifdef LED_USING_SPI void spi1_init() { } #else void spi1_init() { gpio_init_output_mode(LED_RCU, LED_GPIO, LED_CTRL_SCK, GPIO_DRIVE_STRENGTH_MODERATE, 0); gpio_init_output_mode(LED_RCU, LED _GPIO, LED_CTRL_RCK, GPIO_DRIVE_STRENGTH_MODERATE, 0); gpio_init_output_mode(LED_RCU, LED_GPIO, LED_CTRL_SI, GPIO_DRIVE_STRENGTH_STRONGER, 0); gpio_init_output_mode(LED_RCU, LED_GPIO, LED_DATA_SCK, GPIO_DRIVE_STRENGTH_MODERATE, 0); mode(LED_RCU, LED_GPIO, LED_DATA_RCK, GPIO_DRIVE_STRENGTH_MODERATE,0); gpio_init_output_mode(LED_RCU, LED_GPIO, LED_DATA_SI, GPIO_DRIVE_STRENGTH_STRONGER, 0); } void led_74hc595_ctrl_send_byte(uint8_t data) { uint8_t i = 0; LED_CTRL_RCK_LOW; for(i = 0; i < 8; i++) { if(data & 0 x80) { LED_CTRL_SI_HIGH; } else { LED_CTRL_SI_LOW; } data<<=1; LED_CTRL_SCK_LOW; LED_CTRL_SCK_HIGH; } LED_CTRL_RCK_HIGH; delay_us(10); LED_CTRL_RCK_LOW; } void led_74hc595_data_send_word(uint16_t data) { uint8_t i = 0; LED_DATA_RCK_LOW; for(i = 0; i < 16; i++) { LED_DATA_SCK_LOW; if(data & 0x8000) { LED_DATA_SI_HIGH; } else { LED_DATA_SI_LOW; } data<<=1; LED_DATA_SCK_HIGH; } LED_DATA_RCK_HIGH; delay_us(10); LED_DATA_RCK_LOW; } ``` ## Let’s first explain the basic principles of light control. Referring to the schematic diagram above, assuming that we need to light up the red and green lights marked as pin 1, then: Control pin: pin 1 = 1, other pins = 0 (corresponding to QCON7 = 1, QCON6-0 = 0, D1 = 0x80) Data pins: pin 5 and pin 20 = 0, other pins = 1 (corresponding to D2 = 0x7F, D3 = 0x7F) The control logic is: X3 sends 0x80, then X4 sends 0x7F7F. Based on this idea, the program of the revolving lantern is as follows: ``` static uint16_t data_scan_mode[] = {0x7F7F, 0xBFBF, 0xDFDF, 0xEFEF, 0xF7F7, 0xFBFB, 0xFDFD, 0xFEFE}; void led_flash_test(uint8_t COUNT) { uint8_t L1[] = {0 , 1, 2, 3, 4, 5, 6, 7}; uint8_t L2[] = {7, 6, 5, 4, 3, 2, 1, 0}; static uint8_t count = 0; static uint8_t row_count = 0 ; static uint8_t row_flag = 0; uint8_t col_count = 0; static uint8_t col_index = 0; if (count++ > COUNT) { count = 0; if (row_count%2) { col_count = L2[col_index]; } else { col_count = L1[col_index]; } printf("[1] row = %d, col = %d \n", row_count, col_count ); led_74hc595_ctrl_send_byte(ROW_ON(row_count)); led_74hc595_data_send_word(data_scan_mode[col_count]); if (col_index++ == 7) { col_index = 0; if (row_flag) { row_count--; } else { row_count++; } if (row_count >= 7) { row_flag = 1; } else if (row_count <= 0) { row_flag = 0; } } } } ``` ## Show heart shape  ``` static uint16_t data_heart_RED_mode[] = {0xFFFF, 0xFFE7, 0xFFC3, 0xFF81, 0xFF00, 0xFF00, 0xFF99, 0xFFFF}; void led_heart_test(uint8_t COUNT) { static uint8_t count = 0; static uint8_t col_count = 0; if (count++ > COUNT) { count = 0; led_74hc595_ctrl_send_byte(ROW_ON(col_count)); led_74hc595_data_send_word(data_heart_RED_mode[col_count++]); if (col_count > 7 ) { col_count = 0; } } } ``` ## Video! [Revolving lantern effect](https://s2.loli. net/2022/06/05/3T5WP7BqAZEXbGd.gif)  

lugl4313820

Thanks for sharing. You continue to post after the project is completed. You deserve a thumbs up!