max7219_8x8led_4in1.c File Reference

#include "fw_hal.h"

Go to the source code of this file.

Macros
#define	MAX7219_CS   P17
#define	MAX7219_BLOCKS   4
#define	DECODE_MODE   0x09
#define	INTENSITY   0x0A
#define	SCAN_LIMIT   0x0B
#define	SHUT_DOWN   0x0C
#define	DISPLAY_TEST   0x0F

Functions
void	MAX7219_singeWrite (uint8_t index, uint8_t addr, uint8_t dat)
void	MAX7219_multiWrite (uint8_t addr, uint8_t len, uint8_t *dat)
void	MAX7219_init (void)
void	SPI_init (void)
void	main ()

Variables
const uint8_t	numbers []
uint8_t	val [MAX7219_BLOCKS]
uint8_t	character_len = sizeof(numbers) / 8

Macro Definition Documentation

DECODE_MODE

#define DECODE_MODE   0x09

Definition at line 55 of file max7219_8x8led_4in1.c.

DISPLAY_TEST

#define DISPLAY_TEST   0x0F

Definition at line 59 of file max7219_8x8led_4in1.c.

INTENSITY

#define INTENSITY   0x0A

Definition at line 56 of file max7219_8x8led_4in1.c.

MAX7219_BLOCKS

#define MAX7219_BLOCKS   4

Definition at line 53 of file max7219_8x8led_4in1.c.

MAX7219_CS

#define MAX7219_CS   P17

Demo: MAX7219 8x8 LED Matrix 4 in 1 Board: STC8H1K08

P1.3 -> DIN P1.5 -> SCLK P1.7 -> CS

PlatformIO configuration example

[env:stc8g1k08] platform = intel_mcs51 board = stc8g1k08 build_flags = -D__CONF_FOSC=36864000UL -D__CONF_MCU_MODEL=MCU_MODEL_STC8G1K08 -D__CONF_CLKDIV=0x00 -D__CONF_IRCBAND=0x01 -D__CONF_VRTRIM=0x20 -D__CONF_IRTRIM=0xA3 -D__CONF_LIRTRIM=0x03 upload_protocol = custom upload_port = /dev/ttyUSB0 upload_speed = 115200 upload_flags = -p$UPLOAD_PORT -s$UPLOAD_SPEED -e upload_command = ${platformio.packages_dir}/tool-stc8prog/stc8prog $UPLOAD_FLAGS -f $SOURCE

Definition at line 52 of file max7219_8x8led_4in1.c.

SCAN_LIMIT

#define SCAN_LIMIT   0x0B

Definition at line 57 of file max7219_8x8led_4in1.c.

SHUT_DOWN

#define SHUT_DOWN   0x0C

Definition at line 58 of file max7219_8x8led_4in1.c.

Function Documentation

main()

void main

(

void

)

---

| | |_______________________| A B

pos: point to the bit for boundary A lpos: point to the bit for boundary B

Definition at line 160 of file max7219_8x8led_4in1.c.

{
    uint16_t pos = 0, lpos = 0;
    uint8_t i, j, cpos = 0, bpos = 0, tcpos = 0;
 
    SYS_SetClock();
    // Configure GPIO pins before SPI and device
    // DIN(P13)
    GPIO_P1_SetMode(GPIO_Pin_3, GPIO_Mode_InOut_QBD);
    // SCLK(P15), CS(P17) 
    GPIO_P1_SetMode(GPIO_Pin_5|GPIO_Pin_7, GPIO_Mode_Output_PP);
    // Configure SPI and device
    SPI_init();
    MAX7219_init();
 
    while(1)
    {
        lpos = pos + sizeof(numbers) - MAX7219_BLOCKS * 8;
        cpos = lpos / 8;        // char position
        bpos = lpos % 8;        // bit position
        for (i = 0; i < 8; i++) // fill each line
        {
            for (j = 0; j < MAX7219_BLOCKS; j++)
            {
                tcpos = (cpos + j) % character_len;
                val[j] = numbers[tcpos * 8 + i] << bpos;
                tcpos = (cpos + j + 1) % character_len;
                val[j] |= numbers[tcpos * 8 + i] >> (8 - bpos);
            }
            MAX7219_multiWrite(i + 1, MAX7219_BLOCKS, val);
        }
        pos = (pos + 1) % sizeof(numbers);
        SYS_Delay(50);
    }
}

MAX7219_init()

void MAX7219_init

(

void

)

Definition at line 128 of file max7219_8x8led_4in1.c.

{
    for (uint8_t i = 0; i < MAX7219_BLOCKS; i++)
    {
        MAX7219_singeWrite(i, SHUT_DOWN, 0x01);    // 0x00:shutdown, 0x01:normal
        MAX7219_singeWrite(i, DECODE_MODE, 0x00);  // Bypass code B decoder, no-decode operation
        MAX7219_singeWrite(i, SCAN_LIMIT, 0x07);   // Scan-limit, 0:1-digit, 1:2-digits, ..., 7:8-digits
        MAX7219_singeWrite(i, INTENSITY, 0x00);    // 0x00:min, 0xFF:max
        MAX7219_singeWrite(i, DISPLAY_TEST, 0x00); // 0x00:normal, 0x01:test mode
    }
}

MAX7219_multiWrite()

void MAX7219_multiWrite	(	uint8_t	addr,
		uint8_t	len,
		uint8_t *	dat
	)

Definition at line 117 of file max7219_8x8led_4in1.c.

{
    MAX7219_CS = 0;
    while (len--)
    {
        SPI_TxRx(addr);
        SPI_TxRx(*dat++);
    }
    MAX7219_CS = 1;
}

MAX7219_singeWrite()

void MAX7219_singeWrite	(	uint8_t	index,
		uint8_t	addr,
		uint8_t	dat
	)

Definition at line 103 of file max7219_8x8led_4in1.c.

{
    index = index % MAX7219_BLOCKS;
    MAX7219_CS = 0;
    SPI_TxRx(addr);
    SPI_TxRx(dat);
    while(index--)
    {
        SPI_TxRx(addr);
        SPI_TxRx(dat);
    }
    MAX7219_CS = 1;
}

SPI_init()

void SPI_init

(

void

)

Definition at line 140 of file max7219_8x8led_4in1.c.

{
    // MAX7219 can work with frequency up to 20MHz
    SPI_SetClockPrescaler(SPI_ClockPreScaler_4);
    // Clock idles low
    SPI_SetClockPolarity(HAL_State_OFF);
    // Data transfer is driven by lower SS pin
    SPI_SetClockPhase(SPI_ClockPhase_LeadingEdge);
    // MSB first
    SPI_SetDataOrder(SPI_DataOrder_MSB);
    // Define the output pins
    SPI_SetPort(SPI_AlterPort_P12P54_P13_P14_P15);
    // Ignore SS pin, use MSTR to swith between master/slave mode
    SPI_IgnoreSlaveSelect(HAL_State_ON);
    // Master mode
    SPI_SetMasterMode(HAL_State_ON);
    // Start SPI
    SPI_SetEnabled(HAL_State_ON);
}

Variable Documentation

character_len

uint8_t character_len = sizeof(numbers) / 8

Definition at line 101 of file max7219_8x8led_4in1.c.

numbers

const uint8_t numbers[]

Definition at line 61 of file max7219_8x8led_4in1.c.

val

uint8_t val[MAX7219_BLOCKS]

Definition at line 100 of file max7219_8x8led_4in1.c.