Dot Matrix large screen speech sensor--max7219 dot matrix

MAX7219 lattice module can be used with three data lines to achieve 8*8 led lattice control, and do not need to participate in the scanning of single-chip computer, the use is very convenient. More importantly, it supports the use of modular cascade, without increasing the number of IO, the implementation of multi-module control. Therefore, in the large-screen meter, the use of 3 MAX7219 lattice modules into a 8*24 lattice screen.

The use of dot matrix encountered a little trouble, is about cascading use, the network query to the code of each piece of lattice write need to use a separate function, such as:

Write the data to the second piece of MAX7219
void Max7219_write_1 (Uchar Add2,uchar dat2) {
max7219_pincs=0;
Sent (ADD2);
Sent (DAT2);
max7219_pinclk=1; 16.5 clock cycles, data starting from the dout end of the first piece of MAX7219
Sent (REG_NO_OP); Empty operation on the first piece of MAX7219,
Sent (0x00);
Max7219_pincs=1;
}

This is not practical, I dare not imagine the number of lattice modules more cases. Rewrite as follows:

First define the number of modules

#define Max7219_nums 3

//-------------------------------------------
Function: Write data to MAX7219
Entry parameters: Chip: cascaded chip number, 0~max7219_nums-1
Address, DAT

void write_max7219 (Uchar chip, Uchar address, Uchar dat) {
int i;
max7219_pincs=0;
for (i=0;i<max7219_nums;i++) {
if (i==chip) {
Write_byte (address);
Write_byte (DAT);
} else {
Write_byte (REG_NO_OP); Empty operation,
Write_byte (REG_NO_OP); Empty operation
}
}
Max7219_pincs=1;
}

In addition, two functions can also be used as an example of the operation of a dot matrix using the above functions.

//-------------------------------------------
Function: Lattice screen initialization

Entry parameter: None

void Max7219_init (void) {
int i;
for (i=0;i<max7219_nums;i++) {
write_max7219 (i, 0x09, 0x00); Decoding method: BCD code
write_max7219 (i, 0x0a, 0x01); Brightness
write_max7219 (i, 0x0b, 0x07); Scanning limits; 8 x Digital Tube Display
write_max7219 (i, 0x0c, 0x01); Power-down mode: 0, Normal mode: 1
write_max7219 (i, 0x0f, 0x00); Display test: 1; end of test, normal display: 0
}
for (i=0;i<8*max7219_nums;i++)
write_max7219 (I/8, i%8+1, 0); Black screen
}

//-------------------------------------------
Function: Turn off the dot-matrix screen display

Entry parameter: None

void Max7219_sleep (void) {
int i;
for (i=0;i<8*max7219_nums;i++)
write_max7219 (I/8, i%8+1, 0); Black screen
for (i=0;i<max7219_nums;i++) {
write_max7219 (i, 0x0c, 0x00); Power-down mode: 0, Normal mode: 1
}
}

This article from "Tsing Lung Yan Yue" blog, reproduced please contact the author!

Dot Matrix large screen speech sensor--max7219 dot matrix