Hello, I develop a system which contains a real time clock via i2C and is controlled by the computer via the RS232 protocol. In order to develop the I2c part i take the lower functions of the application notes cygnal_i2c.zip and receive the information from the uart via interruption. Each technologie work properly when they are separate but when I want to execute them in the same project i have a conflict: if i receive an event from the uart in the same time as the i2c wait for an acknowledgment from the slave part, the program stack. Have anybody an idea on the subject?