sx8661 Semtech Corporation, sx8661 Datasheet - Page 25

• Manufacturer Part Number: sx8661
• Description: Low Power, Capacitive Button Touch And Proximity Controller 8 Sensors With Led Drivers And Analog Output
• Manufacturer: Semtech Corporation

SX8661
Low Power, Capacitive Button Touch and Proximity Controller
(8 sensors) with LED Drivers and Analog Output
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
In case the application needs different settings than the QSM settings then the SX8661 can be setup and/or
programmed over the I2C interface.
The configuration parameters of the SX8661 can be stored in the Multiple Time Programmable (MTP) Non
Volatile Memory (NVM). The NVM contains all those parameters that are defined and stable for the application.
Examples are the number of sensors enabled, sensitivity, active and Doze scan period. The details of these
parameters are described in the next chapters.
At power up the SX8661 checks if the NVM contains valid data. In that case the configuration parameter source
becomes the NVM. If the NVM is empty or non-valid then the configuration source becomes the QSM. In the next
step the SX8661 copies the configuration parameter source into the Shadow Parameter Memory (SPM). The
SX8661 is operational and uses the configuration parameters of the SPM.
During power down or reset event the SPM loses all content. It will automatically be reloaded following power up
or at the end of the reset event.
The host will interface with the SX8661 through the I2C bus and the analog output interface.
The I2C of the SX8661 consists of 16 registers. Some of these I2C registers are used to read the status and
information of the buttons. Other I2C registers allow the host to take control of the SX8661. The host can e.g.
decide to change the operation mode from active mode to Doze mode or go into sleep (according Figure 9).
Two additional modes allow the host to have an access to the SPM or indirect access to the NVM.
These modes are required during development, can be used in real time or in-field programming.
Figure 21 shows the Host SPM mode. In this mode the host can decide to overwrite the SPM. This is useful
during the development phases of the application where the configuration parameters are not yet fully defined and
as well during the operation of the application if some parameters need small deviations from the QSM or NVM
content.
Host SPM mode
Figure 21
The content of the SPM remains valid as long as the SX8661 is powered. After a power down the host needs to
re-write the SPM at the next power-up.
Figure 22 shows the Host NVM mode. In this mode the host will be able to write the NVM.
Revision v3.2, January 2011
© 2011 Semtech Corp.
www.semtech.com
25