SPI debugging-74HC595 digital tube control experiment

Note: To use the SPI of S3C2440 to control peripherals, you must connect a pull-up resistor to nSSn to ensure normal data transmission. You can find another I/0 port to control the chip select of 74HC595.

74HC595 is an 8-bit serial input to parallel output shift register. 74HC595 pin diagram!

Control schematic diagram:

RCK is also known as STCP. Before collecting data, RCK should be given a low level, and after collecting the signal, it should be given a high level.

RCK (pin 12): The data of the shift register enters the data storage register at the rising edge, and the data of the storage register remains unchanged at the falling edge. I usually set RCK to a low level. When the shift is completed, a positive pulse (at 5V, more than a few tens of nanoseconds is enough. I usually choose microseconds) is generated at the RCK end to update the displayed data.

Control Chart Procedure:

void SPI_TEST(void)
{
int i;
U32 k;
 Uart_Printf("SPI COMMNICATIONn");
 Uart_Printf("SPI0 is master ,SPI1 is slave!n");
 SPI_Init();
 rGPBCON = 0x15400;
 while(1)
 {
 for( i=0;i<19;i++)
 {
 rGPBDAT=0x00;
 while(!(rSPSTA0&0x01));
 rSPTDAT0=data[i];
 delay(1000);

rGPBDAT=0xFF;
delay(1000);
 }
 }
 Uart_Printf("nthat's ok!n");
}
void SPI_Init(void)
{
rGPECON=(2<<26)|(2<<24)|(2<<22) ;
rGPGCON=(3<<14)|(3<<12)|(3<<10)|(3<<6)|(1<<4);
rGPGUP&=0xFF13;
rGPEUP&=0xC7FF;
rSPPRE0=PCLK/ 2/ucSpiBaud-1;
rSPCON0=(0<<5)|(1<<4)|(1<<3)|(0<<2)|(0<<1)|(0<<0);
rSPPRE1=PCLK/2/ucSpiBaud-1;
rSPCON1=(0<<5)|(1<<4)|(0<<3)|(0<<2)|(0<<1)|(0<<0);
rSPPIN0=(0<< 2)|(1<<1)|(0<<0);
rGPGDAT&=0xFFFB;

}
void delay(U32 dly)
{
U32 i;
for(;dly>0;dly--)
for(i=0;i<50000;i++);
}

At the same time, the data transferred out by 74HC595 can be read by SPI

while(!(rSPSTA0&0x01));
k= rSPRDAT1;
Uart_Printf("RX %xn",k);

Enter the picture