Hi
When writing data on the I2c bus in what order should i setup the i2c module?
The way i have it right now is. 1. set slave address register and data counter. 2. set mode register 3. start writing data to data transmit register.
The other issue i am having is that once my data has been sent the bus is still being held busy (i can see from the status register), and I can't seem to free up the bus, even clearing the Bus Busy bit in the status register doesn't help.
Thanks
Jordan
Hello vishal,
Thanks for the quick reply.
Yes, i figured out my mistake regarding Address, i have now set my address to 0x50.
OK, i understood, Count is now = 2.
Few things i have noticed,
Very important, I am only seeing Clk as constant line measuring at 3.3V. Attached is the Screen capture.
Same goes for data.
I am expecting Clock Pulses on the clock line, correct me if i am wrong.... which is not happening in my case.
When i use the Step into function, i can see my I2C registers getting updated with desired values, but no activity on the scope. it just shows constant 3.3V.
If i press the Run function, it sometimes takes the clock low and sometimes, i see no activity at all. Ok, after trying several attempts, atleast it seems , its not pulling the clock low anymore...
I have also attached the screen shot of ccs, with registers being watched.
Hello Vishal, by now u must have guessed my programming ability...
Anyways...
As soon as my programs steps through the start bit (like earlier before), the clock goes low. Attached is the screen capture.
I just changed the IRS bit to 1 as mentioned, no other changes..
Ok,
Here is another screen capture.... I can see only the Address being sent, and then the clock goes low..
Hello Vishal,
The slave device EEPROM which i am using, is a production model device, its works fine if i read/write with other i2c master like NI -8451.
Again. i want to let you know, that i was able to successfully write to the EEPOM just once. But, when i tried the second time, it just did not work any more.
Then i tried changing the pull up values, no effect.
Then i figured, the piccolo uses 3.3V for i2c, whereas my EEPROM uses 5V for i2c. So i am now using a level shifter circuit, still no effect, apart from the i2c lines being pulled up to 5V now.
Now, i am feeling i am stuck at a dead end now. What suggestions do you have for the next steps if any. Is the code working fine for the write, i have attached it again.
//I2C test
#include "DSP2803x_Device.h" // DSP280x Headerfile Include File
#include "DSP2803x_Examples.h" // DSP280x Examples Include File
// Prototype statements for functions found within this file.
void I2CA_Init(void);
void main(void)
{
InitSysCtrl(); // Step 1. Initialize System Control:
InitI2CGpio(); // Step 2. Initalize GPIO only for I2C functionality
I2CA_Init(); // Step 4. Initialize all the Device Peripherals
I2caRegs.I2CSAR = 0x50; //Set slave address
I2caRegs.I2CCNT = 2; //Set count to data bytes pus address
I2caRegs.I2CDXR = 0xFF; //Send Register Address
// I2caRegs.I2CMDR.all = 0x6E20; // Set the full register.
I2caRegs.I2CMDR.bit.TRX = 1; //Set to Transmit mode
I2caRegs.I2CMDR.bit.MST = 1; //Set to Master mode
I2caRegs.I2CMDR.bit.FREE = 1; //Run in FREE mode
I2caRegs.I2CMDR.bit.STP = 1; //Stop when internal counter becomes 0
I2caRegs.I2CMDR.bit.STT = 1; //Send the start bit, transmission will follow
// My I2CSTR (status register) updates to 0x1406.
// SCL goes low indefinitely.
I2caRegs.I2CDXR = 0x00; // Set data to be send.
DELAY_US(10000);
} // end of main
void I2CA_Init(void)
{
I2caRegs.I2CSAR = 0x50; // Slave address - EEPROM control code
I2caRegs.I2CPSC.all = 5; // Prescaler - need 7-12 Mhz on module clk for 60MHz CPU
I2caRegs.I2CCLKL = 30; // NOTE: must be non zero
I2caRegs.I2CCLKH = 60; // NOTE: must be non zero
I2caRegs.I2CIER.all = 0x24; // Enable SCD,XRDY,RRDY,ARDY,NACK interrupts
I2caRegs.I2CMDR.bit.IRS = 1; // Take I2C out of reset, Stop I2C when suspended
return;
}
//EOF
Do you think, its the hardware causing the problems of the i2c lines?
One more important thing, when i do not connect the EEPROM at all, this is the waveform i get.
Ok,
Understood.
Initially, i was not polling the XRDY bit.
In that case, instead of sending my 2 bytes (since count =2) address and checksum, it was just sending checkum. Attached is the scope capture.
Cant i just write to the DXR register as follows
I2caRegs.I2CDXR = addr_mcu[j];
I2caRegs.I2CDXR = chk_sum[j];
If yes, how can i check to see if content in DXR is shifted before i am filling it with 2nd byte (checksum in this case).
From the scope capture, i can see my ACk from the EEPROM, and my 2nd byte (checksum). But, the register address (0x02 in this case) , i think is overwritten in the DXR.