raspberry Pico PIO

[carl336]

Hardware：Raspberry Pi Pico
Software Development Environment：Micropython
Purpose：Turn on a back light（the back light is producing at present, so now I only have LED driver specification：https://imgur.com/MfJhHsf
）
Hello, I am a beginner, learning Micropython with raspberry Pico.

First of all, here is the code that I wrote:
https://paste.fastmirror.net/?31f1116d1dfba6df#2B31qwCJhPRq3Av8h9VXxgP7bzKYS69FMC5PUVhNYVpQ

Here is the diagram that tested by a logic analyzer:
https://imgur.com/cCTkiSQ

And here is the way how I connected Pico with logic analyzer:

GP10 SCK　 →Channel 0
GP12 MOSI →Channel 1
GP11 SCS →Channel 2
GP 17 DISP →Channel 3
GP 19 EXTCOMIN →Channel 4
GP 2 VDD →Channel 5

I'm trying to figure it out now:
How does it send 1 byte at a time, and I want to set it to send 16 bits at a time. How to modify the code?

https://imgur.com/NyNqgEs