Connecting multiple serial devices......

Guest · Posted: Fri Nov 10, 2006 9:25 am

Hi,

It is not clear to me whether I can connect multiple, unique, serial devices together using the same SDA and SCL pins. For example, can a DS1307 realtime clock and a 24C02 EEPROM share the same interface? Is this practical, or is it going to make my life difficult? I ask because I am running short of I/O pins :-(!

Tony

Ttelmah · Guest

Generally, yes you can.
You would get a 'better' response, if you talked about I2C, rather than 'serial'. The latter applies to a whole range of busses (I2C, async serial like RS232/485, SSP etc. etc..). Some of these busses are designed to support multiple devices, and some are not.
I2C, is designed to support multiple addressed devices (this is why the chips have 'addresses), and will work fine. The problems appear, when the devices have fixed addresses, and (for example), you want to control two memories, and their addresses are the same, and cannot be changed.
However provided you can get versions with distinct addresses, everything should be fine. Some chips allow you to select the address using a number of their external pins. I have (for example), boards running a RTC, I2C D-A, FRAM, and a link to another PIC, happily on a single I2C bus.

Best Wishes