How to run IMU in SPI MODE?

Products & Technology XIAO
1

I’m trying to read 6-Axis data from an IMU at high speed (1k/s sampling), but the execution speed is just not fast enough.
So I’m trying to run a sample sketch in SPI_MODE in the hope that I can increase the speed a little, but this doesn’t work.
I know from the library and datasheet that the pin number is probably wrong (default is 10, but maybe 40?) and that there might be a problem with #ifndef, but I’m a novice when it comes to hardware, so I don’t know anything more than that.
I tried to remove the directives, but of course it was rejected :upside_down_face:
Is there any way to use SPI_MODE ? (or, i2c Fast Mode?)

device: Seeed Studio XIAO nRF52840 Sense
IDE: Arduino IDE 2.0.3
core: Seeed nRF52 mbed-enabled Board 2.7.2
library: Seeed Arduino LSM6DS 2.0.3

Thanks.
Ryu

2

Hi Ryu,
according to the XIAO BLE Sense schematic, the on-board IMU is hard-wired in I2C mode only.
The internal I2C bus is “Wire1” and the external “Wire” (pin D4, D5), AFAIK.
HTH
L5

3

Hi L5,
I see!
No wonder it doesn’t work then.
I guess I’ll have to come up with some other solution……
Thanks a lot!
Ryu

1 Like
4

It’s a shame. I was looking to do the same thing. Is there a way to, perhaps not so elegantly, rewire the module without removing the shielding?

Also, could someone post a link to the schematics? I looked and searched, but could not find them.

Where is the interrupt pin from the IMU wired into on the nRF52840? What is the “pin” name in Arduino?

5

Schematics may be found here.
“Seeed Studio XIAO nRF52840 Sense — スイッチサイエンス”

6

Thanks. The schematics helped a little.

I’m still having trouble with an ISR for the IMU. I guess I’ll search a little and post a separate question if I don’t find a solution.