MPL3115A2 Interrupt problem

benjaminlucke — Tue, 03 Feb 2026 22:59:35 GMT

Hy,

we are using the MPL3115A2 but have a problem while using INT1 in altimeter threshold with window. When the interrupt occurs we read out the INT_SOURCE register, but it's always empty. We have the following configuration:

Enable the sensor:

write value 0x00 to reg 0x26. read 0x26 value 0x00. read 0x26 value 0x00.
write value 0x00 to reg 0x27.
write value 0x20 to reg 0x28.
write value 0x00 to reg 0x29.
write value 0x00 to reg 0x2A. read 0x27 value 0x00.
write value 0x98 to reg 0x26. read 0x26 value 0x98.
write value 0x05 to reg 0x13. read 0x12 value 0x05. read 0x26 value 0x98.
write value 0x1A to reg 0x26. read 0x26 value 0x1A. read 0x26 value 0x18. read 0x00 value 0xB0

Then we activate the interrupt:

write value 0x00 to reg 0x26. read 0x26 value 0x00. read 0x26 value 0x00.
write value 0x00 to reg 0x16.
write value 0x00 to reg 0x17.
write value 0x00 to reg 0x19.
write value 0x00 to reg 0x1A.
write value 0x00 to reg 0x27.
write value 0x20 to reg 0x28.
write value 0x28 to reg 0x29.
write value 0x28 to reg 0x2A.
write value 0x28 to reg 0x27.
write value 0xA9 to reg 0x26. read 0x26 value 0xA9.
write value 0x05 to reg 0x13. read 0x12 value 0x05. read 0x26 value 0xA9. read 0x26 value 0xA9.
write value 0xA9 to reg 0x26. read 0x26 value 0x2B. read 0x26 value 0x2B.
write value 0x29 to reg 0x26. read 0x00 value 0x40.

When the interrupt occurs we read the INT_SOURCE register and get always the value 0x00.

Re: MPL3115A2 Interrupt problem

benjaminlucke — Mon, 03 Nov 2014 17:17:45 GMT

The failure was in here:

write value 0xA9 to reg 0x26. read 0x26 value 0xA9.

it should be:

write value 0x81 to reg 0x26

SensorsのトピックMPL3115A2 Interrupt problem

MPL3115A2 Interrupt problem

Re: MPL3115A2 Interrupt problem