at42qt1481 ATMEL Corporation, at42qt1481 Datasheet - Page 45

• Manufacturer Part Number: at42qt1481
• Description: 48-key Qmatrix Ic
• Manufacturer: ATMEL Corporation

5.11
9621B–AT42–06/11
Oscilloscope Sync – SSYNC
AKS technology works for keys that are AKS-enabled anywhere in the matrix and is not
restricted to physically adjacent keys. The QT1481 has no knowledge of which keys are actually
physically adjacent. When enabled for a key, Adjacent Key Suppression causes detections on
that key to be suppressed if any other AKS-enabled key in the panel has a more negative signal
deviation from its reference during the DI process. Once a key reaches detect it stays in detect
as long as the touch remains, regardless of the signal strength on any other AKS-enabled keys.
This feature does not account for varying key gains (burst length) but ignores the actual negative
detection threshold setting for the key. If AKS-enabled keys have different sizes, it may be
necessary to reduce the gains of larger keys to equalize the effects of AKS technology. The
signal threshold of the larger keys can be altered to compensate for this without causing
problems with key suppression.
Adjacent Key Suppression works to augment the natural moisture suppression of narrow gated
transfer switches creating a more robust sensing method.
AKS Default value:
The S_Sync pin can output a positive pulse oscilloscope sync that brackets the burst of a
selected X line. More than one burst can output a sync pulse as determined by the Setups
parameter SSYNC for each X line (see
This feature is invaluable for diagnostics; without it, observing signals clearly on an oscilloscope
for a particular burst is very difficult.
The bits of this Setup byte are allocated as shown in
Table 5-3.
Note:
This function is supported in Atmel’s QmBtn PC software.
SSYNC Default value:
Bit
7
6
5
4
3
2
1
0
STS_DEBUG shares the use of Pin 43 with SSYNC, but only one feature should be
enabled at a time. To prevent interference, all SSYNC bits should be set to zero (Off) if
Debug output is desired.
Scope Sync Output When Burst On...
SSYNC Bits
0 (Off)
X7
X6
X5
X4
X3
X2
X1
X0
0 (Off)
Table
5-3).
Table
5-3.
AT42QT1481
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