VL53L1X hanging on first wait for data

[SK.61]

I have a VL53L1X connected to a multi-slave I2C bus hosted by a broadcom bcm2835 running linux (4.19). I have configured the `vl53l1_platform.c` from the api ("stsw-img007") to use the <linux/i2c-dev.h> interface with tracing and see bi-direction communication. However, after that `StartMeasurement` call, GetMeasurementDataReady consistently reports that data is not ready, despite waiting for minutes. Since there is no published i2c command/register list/help (?), I am working in the dark. Can someone familiar with this device's i2c interface take a look? Here's the i2c trace log:

Fail; line: 173, expected: 2, got: -1, errno: 121

Fail; line: 173, expected: 2, got: -1, errno: 121

Fail; line: 173, expected: 2, got: -1, errno: 121

Read register: 0x00e5 = 03

wrote register: 0x0000 = 00

wrote register: 0x0000 = 01

Read register: 0x00e5 = 03

Read register: 0x00e5 = 03

Found (booted) device.

Read register: 0x010f = ea cc 10

Validated device.

Read register: 0x002e = 00

wrote register: 0x002e = 01

Read register: 0x0001 = 29 02 10 00 2c bd 1e 81 80 07 95

Read register: 0x000d = ff f7 db bf ff 0f 00 11 01 00 00 00 00 00 00 00 00 00 00 00 39 00 14

Read register: 0x010f = ea cc 10 ff fe 2c 04 03 3c 3f 01 00 01 2a 03 ff ff ff fe 7e bb ff ff 7f ff ff ff ff fd bf ff ff ff ff ed fe de ff ff df 3f ff fe ff 7f fd df 47 55

Read register: 0x00de = 00 25

DataInit completed

StaticInit completed

wrote register: 0x0001 = 29 02 10 00 2c bd 1e 81 80 07 95 00 ff f7 db bf ff 0f 00 11 01 00 00 00 00 00 00 00 00 00 00 00 39 00 14 0a 00 00 00 00 00 00 00 00 00 00 00 11 02 00 02 08 00 08 10 01 01 00 00 00 00 ff 00 02 00 00 00 00 00 20 0b 00 00 02 ff 21 00 00 01 00 00 00 00 8c 00 00 38 ff 01 00 14 00 17 02 f3 0f 03

 8b 0d 01 68 00 c0 08 b8 00 00 00 99 c8 00 00 03 00 00 00 00 00 02 0f 0d 0e 0e 03 00 02 6a 44 db 02 00 00 01 01 21

StartMeasurement completed

Read register: 0x010f = ea cc 10

Read register: 0x0031 = 03

Read register: 0x0031 = 03

Read register: 0x0031 = 03

Read register: 0x0031 = 03

...

[Julien NGUYEN · Accepted solution]

​Hi Dominic, I would go to ST.COM to download the STSW-IMG013 (VL53L1X LINUX Example Code), to inspire from this example to build your own code. Please note that it is not a Linux driver, it is a Linux example code running in the user space. Thanks, Julien

[John E KVAM]

The most common problem is that although the read-byte and write-byte work there can be a byte-swap or word-swap issue. When this happens it looks like everything is set up, but it's not correct.

The platform.c file in STSW-img007 is basically empty. Can you verify that it's filled in?

If all you want to do is basic ranging consider the ultra-lite driver (STSW-IMG009). It's less functional, but a lot smaller, and more clear.

It has a lot of example code which should get you going as well.

[SK.61]

That almost worked out of the box, but it shows me how to use this api. I was thinking there had to be a simpler way then that monstrous api. Thanks.

[SK.61]

Julien beat you to it, with an answer that actually works. Yes, the ultra-lite is probably the best choice for me, but my original intent was to confirm the i2c trace I posted, including potential byte-swapping, as the actualy meaning (and correct order) of the i2c commands are not published.

If you had actually read the question I would hope you could see that I was getting 2-way communication, and therefore obviously didn't leave the platform file empty like the idiot you so quickly assumed me to be.

[John E KVAM]

Julien is a good man, but he cheated. He lives in Europe so he had an 9 hour jump on me. He's also a good friend.

I'm glad you're happy.