User Manual
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9570H–AT42–02/10
AT42QT1110-MZ/AT42QT1110-AZ
REPEAT_TIME: selects the “repeat” time when “Timed” is selected as the trigger to start key
acquisition. The number entered is a multiple of 16 ms. If “0” is entered, the device will operate
in a continuous “free run” mode; that is, the QT1110 will not sleep after its cycle is completed but
will begin the next key acquisition cycle immediately.
Default KEY_AC value: 1 (timed)
Default MODE value: 0 (7-key mode)
Default SIGNAL value: 1 (parallel)
Default SYNC value: 1 (edge)
Default REPEAT_TIME value: 2 (32 ms cycle)
7.5 Address 1: Guard Key/Comms Options
GUARD_KEY: specifies the key (0 to 10) to be used as a guard channel (see Section 2.3 on
page 7) .
GD_EN: enables the use of a guard key; 0 = disable, 1 = enable.
SPI_EN: enables the Quick SPI interface; 0 = disable, 1 = enable (see Table 7-4).
See Section 4.1.6 on page 16 for details of the Quick SPI Mode report.
To exit this mode (and clear the “SPI_EN” bit), the command “0x36” should be sent. To save the
settings to EEPROM and make Quick SPI mode active on startup, send the “Store to EEPROM”
command (0x0A). Any other data sent is ignored in Quick SPI mode.
CHG: the CHANGE
pin mode (see Section 4.5 on page 17):
0 = “Data” mode. In this mode the “Change” pin is asserted to indicate unread data.
1 = “Touch” mode. In this mode the “Change” pin is asserted when a key is being touched
or is in detect.
CRC: enables or disables CRC; 0 = disable, 1 = enable. When this option is enabled, each data
exchange must have a CRC byte appended.
When report or setup data is being returned by the QT1110, a 1-byte checksum is returned. The
host should confirm that this checksum is correct and, if not, should request the report again.
Table 7-3. Guard Key/Comms Options
Address Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
1 GUARD_KEY GD_EN SPI_EN CHG CRC
Table 7-4. Status Information Bytes
Byte Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0 Counter
1 Key 3 status Key 2 status Key 1 status Key 0 status
2 Key 7 status Key 6 status Key 5 status Key 4 status
3
Reserved Key 10 status Key 9 status Key 8 status
4 Key 3 error Key 2 error Key 1 error Key 0 error
5 Key 7 error Key 6 error Key 5 error Key 4 error
6
Reserved Key 10 error Key 9 error Key 8 error