hello, im fairly new to the electronics field so excuse me if i ask lots of questions.
a quick background: im planning on building a device for bicyclers and runners mainly. the device will monitor the vital signs of the user and alert them for any health danger according to collected info from sensors such as respiration, temperature, pulse, blood pressure and oxygen.

the problem is i currently have 3 UART communications, and im trying to get it down to 2 to be able to use 1 uC instead of 2. in order to get only 2 UART communications, i must use an I2C pulse oximeter instead of a UART one [the other 2 remaining UARTs cannot be replaced with an other communication].

https://www.olimex.com/Products/Modules/Biofeedback/MOD-PULSE/
in the link above there's a pulse oximeter board using UEXT connector.
since google could not help me out, im seeking your help:
1. can the board be connected to an other uC with an via the I2C pins, taking in consideration there are about 2-3 other I2C sensors?
2.how well will it work using 2 different uCs in one program? i haven't decided yet on the main uC of the project since i need to be certain there are only 2 sensors that must have UART.

hope its not too much and that you were able to understand my issue.

 

With a quick glance at the uC that is on the MOD-PULSE (MSP430FG439), it doesn't seem to have I2C built in, just UART and SPI. You can use SPI to interface with numerous uC's, you just need a slave select pin for each one.

Since you haven't yet selected the main uC for your project, might I suggest you take a look at the ATxmega line? They have uC's with 5 UARTS which might be nice for connecting the variety of sensors you are looking at.