8-bit Microcontrollersのトピックi2c connection with a DEMO9S08QG8

i2c connection with a DEMO9S08QG8

marmor — Wed, 30 Jul 2014 10:40:59 GMT

Hi I am trying to connect the DEMO9S08QG8 to a lcd through Connection i2c but not working. This is the library I'm using for i2c communication does anyone know tell me what is wrong? I've been modifying a thousand times but do not know what the problem is

Mensaje editado por: Maria Mor

Original Attachment has been moved to: i2c.rar

Re: i2c connection with a DEMO9S08QG8

iansmusical — Wed, 30 Jul 2014 13:49:01 GMT

Hi Maria,

I can't completely see a path through your code but presuming your S08 is the master and the LCD is a slave, I would have a look at the IICC MST bit. I'm not sure if you have it set when you start a transmission?

I'm also not sure that the two lines below the /* Reset 24c02 */ comment are necessary.

Thanks,

Ian

Re: i2c connection with a DEMO9S08QG8

marmor — Wed, 30 Jul 2014 15:16:20 GMT

Hi Ian.

Effectively the DEMO9S08QG8 is the master and the slave plantalla lcd.
Regarding the MST bit, I think it's okay, it has to be 0 while not want to send a stop signal and when you want to stop sending data is the i2c_stop_condition () function to send the stop sign.

I do not understand what you mean with the "two lines below the / * Reset 24c02 * / comment".

I appreciate your comment and you've taken the time to look at the code.

Re: i2c connection with a DEMO9S08QG8

iansmusical — Thu, 31 Jul 2014 07:50:20 GMT

Hi Maria,

Here is some code I used recently to read a status byte from an I2C slave. It looks quite similar to your code but I have to admit I am no expert on I2C ;-)

IICC_TXAK = 0;

IICC |= 0x30; // Generate START

IICD = 0xEE; // write to slave device

while (!IICS_IICIF); // wait until flag is set

IICS_IICIF=1; // Clear the int flag

while(IICS_RXAK); // Check for RXAK

IICD = 0xD0; // write command

while (!IICS_IICIF); // wait until flag is set

IICS_IICIF=1; // Clear the int flag

while(IICS_RXAK); // Check for RXAK

IICC_RSTA = 1; // setup repeated start

IICD = 0xEE|1; // (slave_address)|(RW = 1), read from slave

while (!IICS_IICIF); // wait until flag is set

IICS_IICIF=1; // Clear the int flag

while(IICS_RXAK); // Check for RXAK

IICC_TX = 0; // Setup to receive

IICC_TXAK = 1; // Acknowledge disable

RD_data = IICD; // Dummy read

while (!IICS_IICIF); // Wait until IBIF flag is set

IICS_IICIF=1; // Clear the flag

IICC_MST = 0; // Generate STOP

RD_data = IICD; // Read data

The MST bit is set on the "// Generate start" line but I can't fully see how it is configured in your code taken on board the comments you made in your email.

What I meant by the comment is that I don't think you need the I2C start and stop function calls under the /* Reset 24c02 */ comment, unless of course a 24c02 does require these calls :-) Usually slaves by default are listening for I2C bus activity etc.

Thanks,

Ian