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RE: I2c and Avalon Bus

by K@nt :: Rate this Message:

Hello,

I use Signal Tap II Logic Analyser in Quartus, and I see a "normal" activity on SCl and SDA. I chose 10khz for Scl clock.

TIP flag work, and Start and Stop signals are detected. I've just a problem with RxACK flag.

I've defined : OC_I2C_ACK (1<<3)

Is there an other way to check communication between I2C Master and the slave ?

Thank you

Regards

Richard Herveille wrote:

Can you hook up an oscilloscope and see any activity on SCL/SDA??

Richard

-----Original Message-----
From: cores-bounces@opencores.org [mailto:cores-bounces@opencores.org] On
Behalf Of K@nt
Sent: 29 May 2008 10:53
To: cores@opencores.org
Subject: [oc] I2c and Avalon Bus

Hello all,

I'm currently working on opencores I2C master (VHDL version) to
the NIOS 2 processor via the Avalon bus.(Stratix II)
There is an older post about this subject but I can't resolved my problem.

So I've used i2c_master_top_avalon.vhd and I've created a wrapper to use
this component with Avalon bus
http://www.nabble.com/file/p17530366/oc_i2c_master.vhd oc_i2c_master.vhd

I've configured the component(
http://www.nabble.com/file/p17530366/component.jpg ) and attached this to a
NIOS 2 processor.( http://www.nabble.com/file/p17530366/sopc.jpg )

I've assigned Sda ans Scl http://www.nabble.com/file/p17530366/pin.jpg

So I use I2c to configure a video camera (
http://ltc.cit.cornell.edu/courses/ee476/FinalProjects/s2006/jzs3_da65/jzs3_
da65/C3088.pdf
http://ltc.cit.cornell.edu/courses/ee476/FinalProjects/s2006/jzs3_da65/jzs3_
da65/C3088.pdf
) but i can't set this !!

I think the problem is it can't recognize the slave (video camera), in fact
when I write a value into the register of the video camera I'm waiting for
the TIP flag and RxACK flag but the RXACK always stay at '1'...

At start I've thought there was a problem with the slave adress but i've
tested all the values between 0 and 255 with no success !!!

An exemple of my code to write into slave's register :

// address : address of the slave
// reg : address of the slave's register
// data : value wich write in the slave's register

void i2c_write(unsigned char address, unsigned char reg, unsigned char data)
{

// write address
IOWR_I2C_TXR(address);
IOWR_I2C_CR(OC_I2C_STA | OC_I2C_WR | OC_I2C_ACK );
i2c_wait_tip();
i2c_rxack();

// write register address
IOWR_I2C_TXR(reg);
IOWR_I2C_CR(OC_I2C_STA | OC_I2C_WR | OC_I2C_ACK);
i2c_wait_tip();
i2c_rxack();

// write data
IOWR_I2C_TXR(data);
IOWR_I2C_CR(OC_I2C_WR | OC_I2C_STO);
i2c_wait_tip();
i2c_rxack();
}

void i2c_rxack(void){
while ((IORD_I2C_SR & OC_I2C_RXACK)> 0 ) {}
}

I've initialized CTR (0x80) before write into slave's register

Can I have some help, please ?

Thank you very much

Regards
--
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