Connii MM

Connii MM is a small, compact, easy-to-use solution for a PC driven I2C transmitter and receiver. The I2C interface works as an I2C multimaster device. Thus, it is able to drive buses running multiple I2C bus masters.

Additionally, Connii MM is a limited I2C monitor for traffic up to 400kHz.

This multimaster behaviour and the I2C monitor are the main differences between Connii MM and Connii, which is a singlemaster only.

Interfacing

PC connection via USB bus
I2C connection via Mini-DIN connector
I2C buses operating at a range of 2.7 - 5.5 Volt can be attached

Features

I2C Multimaster: Several I2C master may share the bus
Simple I2C Monitor, tracing up to 400kHz (see limitations below)
Clock stretching detection: A slave may stretch the bus
TWI bus support

ESD protected I2C, IEC compatibility according to
EN 61000-4-2 (ESD): Air - 15kV, Contact - 8kV

Limitations

The I2C Monitor does only recognize regular I2C transfers, no I2C error conditions etc., thus it is not well suited for finding problems on I2C communication level. The monitor stretches SCL, in particular on SCL clock speeds above 120kHz, i.e. the SCL line is held low occasionally. That may lead to problems with master or slave devices that do not support SCL stretching (like some I2C single master implementations).
Tracii XL 2.0 offers a more sophisticated I2C Monitor, which includes time stamps for every byte and error recognition.
For proper tracer mode operation, please connect additional pullup resistors of 7 kOhm or less to SDA and SCL.