Hi,
Has anyone tried talking to a DS1393 or similar 3-wire RTC from either a PIC or AVR (or similar) - these RTCs are not SPI - they have a bi-directional I/O pin.
Thanks,
Mike
Hi,
Has anyone tried talking to a DS1393 or similar 3-wire RTC from either a PIC or AVR (or similar) - these RTCs are not SPI - they have a bi-directional I/O pin.
Thanks,
Mike
Isn't it really just I2C protocol with a chip select as the "third" wire?
I'd be very 'wary' about chosing this chip, since it is no longer listed by Dallas/Maxim, with the data sheet 'links', going to a blank page...
Best Wishes
listed
Hmm.... I just went to
The datasheet link worked fine for me as well. It's one datasheet for the DS1390, DS1391, DS1392, and DS1393. Where did you look?
I'm using a DS1302 for a project which also has only 3 wires. It's really simple and just like SPI, except that it's half duplex.
You can easily bit bang it. Switch the data in/output to output, make /CS low, output 8 databits+clocks, then change the in/output to input, and issue the neccessary clocks and sample the input. 20-25 lines of C code.
something like:
(assuming AVR, port B... 0=cs 1=dat 2=clk)
#define CS 1 #define DAT 2 #define CLK 4 . . . DDRB|=DAT; // switch the data line to output PORTB&=~CS; // select the chip for (i=0;i
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