Olimex Support Forum

Microcontrollers => PIC => Topic started by: samuele on October 17, 2012, 03:45:58 pm

Title: PIC-WEB and I2C
Post by: samuele on October 17, 2012, 03:45:58 pm
Hi,
I'm planning to use the PIC-WEB platform for one of my company projects.

The project requires to read some sensors (Sensirion SHT21/25) through I2C and provide a web interface to show the values read from the sensors.
I was thinking of using the SDA/SCL pin on the UEXT connector on the PIC-WEB to interface the PIC controller to the sensors.
Looking at the schematic I have seen that those pins are not connected to the MSSP port of the PIC, because the MSSP port of the PIC is used in SPI mode to connect the AT45DB011 flash chip, and the PIC18F67J60 has only one MSSP port.
So, my question is: how to get I2C on the SDA/SCL pins on the UEXT connector? Do I have to implement a bitbanged I2C? Or it could be possible to share the MSSP port pins on the UEXT connector with my I2C sensors?


Regards,
Samuele.
Title: Re: PIC-WEB and I2C
Post by: LubOlimex on October 22, 2012, 05:00:45 pm
Hello Samuele,

Yes. The SCL and SDA signals on the UEXT can be used as I2C without problems.

The older revisions of PIC-WEB had this problem but PIC18F67J60 has separate I2C and SPI interfaces.

Note that we have just updated the demo software to the latest stack version: https://www.olimex.com/Products/PIC/Development/PIC-WEB/resources/PIC_WEB_5_42.zip (https://www.olimex.com/Products/PIC/Development/PIC-WEB/resources/PIC_WEB_5_42.zip)

Best regards,
Lub/OLIMEX
Title: Re: PIC-WEB and I2C
Post by: cgcallebs on November 16, 2012, 12:20:06 am
Why is it asking me for a password when I try to extract it?
Title: Re: PIC-WEB and I2C
Post by: cgcallebs on November 16, 2012, 02:50:06 am
OK, you can tell I am a newbie. Once I read the agreement documents things became clear.