Datasheet

DS_INLC10AQ Revision 1.0_B

Inova Semiconductors Confidential

Page 12 of 35

4.0

Functional Description

4.1

Serial Communication

Figure 7

– Serial communication

The attachment to the adjacent devices in the chain is made up by two bidirectional differential serial

communication lines. The direction towards the controlling microcontroller device is referred to as the

“upstream” connection. The opposite direction towards the end of the chain is the “downstream” link. Both

links are controlled by the communication unit. Incoming command frames from upstream and responses

from downstream are passed to the main unit which is responsible for command processing and overall

device control. Commands always originate from the controlling microcontroller. The microcontroller is

referred to as the “host” in this document.

The gross data rate on the serial line is 2Mbit/s, i.e. each bit has a nominal duration of 500 ns. As the on-

die oscillator has a very limited accuracy, the actual bit time may vary significantly. The whole system is

designed for a maximum oscillator variance of ±30%. With the nominal oscillator frequency being 16 MHz,

the actual frequency range is 11.2-20.8MHz.

The device directly attached to the host does not use the differential line mode on the upstream side. Instead

a single-ended line mode is used. The single-ended mode is intended to allow for an easy attachment to

industry standard microcontrollers. Both single-ended lines require an external pull-up at the microcontroller

to 5V.