07-15-2019 02:11 PM
Hello,
we are currently using a system based on the Dialog IoT sensor with BMI160+BMM150.
I see now that BMI270 is a possible successor of BMI160. I have three questions:
1) The sensor is pin compatible. Are all SPI commands (registers) that were used in BMI160 the same in BMI270, or do I have to expect lots of changes in the code?
2) For the BMI160, the current consumption with "significant motion detector" is stated in the datasheet as max 20µA. I am missing this info for BMI270, we want to use it to wake up our MCU via interrupt.
3) Is the BMI270 the best choice for our application? We are not using any "smart" features, we just need low power and up to ~100Hz. What about the BMI26x series? When will it be available?
Thanks,
Johannes
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07-16-2019 11:40 AM
Hi Johannes
@jmuellers wrote:1) The sensor is pin compatible. Are all SPI commands (registers) that were used in BMI160 the same in BMI270, or do I have to expect lots of changes in the code?
Migrating to BMI270 definitely falls into the "lots of changes in the code" category. Mainly because the BMI270 requires a 8kB firmware image to be loaded at every power-on before it can be used.
@jmuellers wrote:
2) For the BMI160, the current consumption with "significant motion detector" is stated in the datasheet as max 20µA. I am missing this info for BMI270, we want to use it to wake up our MCU via interrupt.
We don't have a specific current consumption number for BMI270, but it is faire to say it should be "in the same ballpark". Definitely between 10 and 40uA. But please note that significant motion is a peculiar interrupt designed for Android devices which combines step-counter and acitivity recognition data to duty-cycle the GNSS chip. For IoT devices typically the any-motion interrupt is used.
@jmuellers wrote:3) Is the BMI270 the best choice for our application? We are not using any "smart" features, we just need low power and up to ~100Hz. What about the BMI26x series? When will it be available?
All BMI2xx are in the same product family. At the moment, BMI270 is the only part number of this family available through distribution. For low-power designs definitely the BMI270 is the best choice, since the current consumption >25% lower with the gyroscope active.
BMI270 vs BMI160 has a much improved accelerometer performance, and gyroscope with lower current consumption.
07-18-2019 05:28 PM
Thank you for the info.
So, if we are not using any "smart" features, just direct access to acc and gyro, there is no direct successor to the BMI160 that has the same or similar digital interface, but better specs or lower power - did I understand that correctly?
07-19-2019 07:43 AM
07-22-2019 02:20 PM - edited 07-22-2019 02:25 PM
Yes, I understood, but I forgot to refer to your most important answer, sorry:
Migrating to BMI270 definitely falls into the "lots of changes in the code" category. Mainly because the BMI270 requires a 8kB firmware image to be loaded at every power-on before it can be used.
At the moment we don't have the capacity for too many changes on the software side, so what I really meant was:
There is no (variation of the) successor that only has better specs, but does not require any software changes whatsoever for simple operational modes?
And, to clarify, when I asked whether they have the same interface, I was not talking about the protocol, but rather the whole command set, or register addresses. Is this also the case?