sx8645 Semtech Corporation, sx8645 Datasheet - Page 71

• Manufacturer Part Number: sx8645
• Description: Ultra Low Power, Capacitive Button And Wheel Touch Controller 12 Sensors With Enhanced Led Drivers
• Manufacturer: Semtech Corporation

ADVANCED COMMUNICATIONS & SENSING
6.6.1
The SPM write can be done in any mode (Active, Doze, Sleep). Writing the SPM in Sleep is useful to avoid
potential transient behaviors.
The SPM must always be written in blocks of 8 bytes. The sequence is described below:
The complete SPM can be written by repeating 16 times the cycles shown in Figure 54 using base addresses
0x00, 0x08, 0x10, …, 0x70, 0x78. Between each sequence the host should wait for INTB (Active/Doze) or 30ms
in Sleep.
In Active or Doze mode, once the SPM write sequence is actually applied, the INTB pin will be asserted and
IrqSrc[5] set. In Sleep mode the SPM write can be actually applied with a delay of 30ms.
The host clears the interrupt and IrqSrc[5] by reading the IrqSrc register.
Revision 7_5, February 10
1. Set the I2C in SPM mode by writing “01” to SpmCfg[5:4] and SPM write access by writing ‘0’ to SpmCfg[3].
2. Write the SPM base address to SpmBaseAddr (The base address needs to be a value modulo 8).
3. Write the eight consecutive bytes to I2C address 0, 1, 2, …7
4. Terminate by writing “000” to SpmCfg[5:3].
SPM Write Sequence
Figure 54: SPM Write Sequence
Touch Controller (12 sensors) with Enhanced LED Drivers
© 2010 Semtech Corp.
71
Ultra Low Power, Capacitive Button and Wheel
DATASHEET
www.semtech.com
SX8645