Reg:- RTC using I2c

Cheeky bugger !

Check you're writing to the correct address !

Graham

Respected Sir

Thanks for ur reply.As per your direction i have checked the address and i am writing only to the seconds register. Its address is 0x80 for writing and 0x81 for reading and no slave ID for ds 1302 is given in the data sheet. Please give me the steps to trouble shoot it. Regards Alagu Sakthi.

Are you confident about the proper operation of your I2C interface ? For example have you used it with another simple peripheral ?

I don't see you sending a command byte ( see page 6 of the data sheet ).

Graham

Sir I am tring the i2c between two Aduc841 microconverter. The analog devices application note uc001 explains the i2c between the same.

The UART functions are omitted and only the transceiving function is written for both slave and master and are fused seperately in two eval boards.

My code structure is

main { initialisation set data(xxxx); while(1) { getdata(); } } set data(xxxx) { write(0x80,xxxx); //80(adress) and xxxx data. }

write(addr,data) { start(); senddata(addr); senddata(data); stop(); }

start() { when clk is high sda is puled low; }

senddata(xxxx) { in this func the byte is send bit by bit with MSB first. getack(); // ack given in s/w.

stop() { when clk is high sda is puled high; }

getdata() { sec = read(0x81); }

char read(0x81) { Startt(); SendData(0x81); Receive_Byte(); Stop_Bit(); return(readdata); }

receive_byte() { all the 8 bits received from MDI is stored temporarily in read data variable and returned. }

this code is for the master mode only.

|||y for the slave mode the interrupt polling is done and no output is obtained. kindly give me the suggestions.

regards Alagu.

You must be using a 'library routine' for your write procedure I assume ?

It seems to me that you are not initiating the data transfer corrctly as I understand it.

You need to send the 'command byte' without any data first to tell the device how you want it to respond.

" COMMAND BYTE Figure 4 shows the command byte. A command byte initiates each data transfer. The MSB (bit 7) must be a logic

1. If it is 0, writes to the DS1302 will be disabled. Bit 6 specifies clock/calendar data if logic 0 or RAM data if logic 1. Bits 1 to 5 specify the designated registers to be input or output, and the LSB (bit 0) specifies a write operation (input) if logic 0 or read operation (output) if logic 1. The command byte is always input starting with the LSB (bit 0). "

from page 6 of the data sheet.

Graham

The info about the command byte is a little ambiguous.

However reading more - I noticed that using 080H as the command address is a

You ned to use 081H to read.

All the read 'addresses' are 'odd'. 083H etc....

Graham

Sir I have tried betwn two Aduc's.I have just only transmitted from the master and no receive process is done.

So the slave should respond to receive the data onlly not to transmit to master.

This is kept in interrupt polling such as, when slave receives data from master the i2ci bit set in the I2CCON register of aduc841.(slave mode)

so in the interrupt routine i have just compliment a port pin to indicate that the slave had receive or responded to the master's request.

whether my procedure is correct? or i want to do it in some other fashion.

slave routine

configur aduc841in slave mode enable interrupts

wait till interrupt occurs // interrupt occurs when the master transmits to slave and the slave responds to it.

if (interrupt) { cpl port // to indicate the slve's response }

is this is correct?

regards alagu.