AT42QTAN0040 ATMEL [ATMEL Corporation], AT42QTAN0040 Datasheet - Page 3

• Manufacturer Part Number: AT42QTAN0040
• Description: Driving the AT42QT2160 QMatrix Sensor IC
• Manufacturer: ATMEL [ATMEL Corporation]

3.3
4. Demonstration Program
4.1
10702A–AT42–07/08
Interface Timing
The main() Function
Figure 3-1
in its sense status by driving the CHANGE pin low. In this context, sense status includes bytes 2
through 6 of the address map. In response to the QT2160 driving CHANGE low, the host reads
all of bytes 2 – 6. The QT2160 releases the CHANGE pin when all changed bytes have been
read. Handshaking logic within the QT2160 guarantees that any unread changes in any status
byte will cause CHANGE to be driven low, even if this occurs while the device is being read.
Figure 3-1.
A simplified flowchart for the QT2160 demonstration program is shown in
program flow is encapsulated in the main() function of the C code (see
Figure 4-1.
CHANGE
I2C-comaptible
illustrates the interface timing used in the example. The QT2160 signals any change
QT2160 Interface Timing
Simplified Flowchart for the Demonstration Program
Change in
status
Cleared by
High
read
Status read
Establish comms
Read QT2160
Display Status
to QT2160
RES set?
CHANGE
on LEDs
Status
Main()
pin?
Low
No
Driving the AT42QT2160
Yes
Change in status
during read
Status read
Initialize
QT2160
Section 6 on page
Cleared by following
read
Figure
Status read
4-1. The
8).
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