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https://github.com/marqs85/ossc
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100 lines
3.6 KiB
C
100 lines
3.6 KiB
C
/* these test were created to show how to use the opencores I2C along with a driver found in
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* the I2C_opencores component to talk to various components.
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* This test example uses a littel daughter board from microtronix
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* it has a I2c to parallel chip (PCA9554A) a EEPORM and real time clock.
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* I chose not to impliment the real time clock.
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* But you can see how the calls work
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* There are only 4 functions associalted with the I2C driver
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* I2C start - send start bit and address of the chip
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* I2C_read - read data
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* I2C_write. - write data
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* how and when each of these get used is based on the device you
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* are talking to.
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* See the driver code for details of each function.
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* */
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#include <stdio.h>
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#include "system.h"
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#include "i2c_opencores.h"
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int main()
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{
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int data;
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int i;
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// testing the PCA9554A paralle interface
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// this writes a 5 to the leds and read the position of the dip switches.
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printf(" tesing the PCA9554A interface the\n the LEDS should be at a 5 \n");
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// address 0x38
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// set the fequesncy that you want to run at
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// most devices work at 100Khz some faster
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I2C_init(I2CA_BASE,ALT_CPU_FREQ,100000);
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I2C_init(I2CA_BASE,ALT_CPU_FREQ,100000);
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// for the parallel io only the first 4 are output s
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// the PCA9554A uses a command word right after the chip address word ( the start work)
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I2C_start(I2CA_BASE,0x38,0);// chip address in write mode
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I2C_write(I2CA_BASE,3,0); // write to register 3 command
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I2C_write(I2CA_BASE,0xf0,1); // set the bottom 4 bits to outputs for the LEDs set the stop
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// now right to the leds
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I2C_start(I2CA_BASE,0x38,0); // address the chip in write mode
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I2C_write(I2CA_BASE,1,0); // set command to the pca9554 to be output register
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I2C_write(I2CA_BASE,5,1); // write the data to the output register and set the stop
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//now read the dip switches
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// first set the command to 0
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I2C_start(I2CA_BASE,0x38,0); //address the chip in write mode
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data = I2C_write(I2CA_BASE,0,0); // set command to read input register.
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I2C_start(I2CA_BASE,0x38,1); //send start again but this time in read mode
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data = I2C_read(I2CA_BASE,1); // read the input register and send stop
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data = 0xff & (data >>4);
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printf("dip switch 0x%x\n",data);
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printf("\nNow writing and reading from the EEPROM\n");
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//address 0x50-57
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I2C_start(I2CA_BASE,0x50,0); // chip address in write mode
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I2C_write(I2CA_BASE,0,0); // write to starting address of 0
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// now write the data
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for (i=0;i<7;i++) // can only write 8 bites at a time
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{
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I2C_write(I2CA_BASE,i,0); // writ the data
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}
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I2C_write(I2CA_BASE,i,1); // write last one with last flag
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while ( I2C_start(I2CA_BASE,0x50,0)); // make sure the write is done be fore continuing.
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// can ony burst 8 at a time.
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I2C_write(I2CA_BASE,8,0); // write to starting address of 8
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// now write the data
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for (i=0;i<7;i++) // write the next 8 bytes
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{
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I2C_write(I2CA_BASE,i+8,0); //
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}
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I2C_write(I2CA_BASE,i+8,1); // write last one with last flag
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while ( I2C_start(I2CA_BASE,0x50,0)); // make sure the write is done be fore continuing.
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//now read the values
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// first set the command to 0
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I2C_start(I2CA_BASE,0x50,0); //set chip address and set to write/
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I2C_write(I2CA_BASE,0,0); // set address to 0.
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I2C_start(I2CA_BASE,0x50,1); //set chip address in read mode
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for (i=0;i<15;i++)
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{
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data = I2C_read(I2CA_BASE,0); // memory array
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printf("\tdata = 0x%x\n",data);
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}
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data = I2C_read(I2CA_BASE,1); // last memory read
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printf("\tdata = 0x%x\n",data);
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printf("Hello from Nios II!\n");
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return 0;
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}
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