Nuvoton NUC980 IIOT Board Experiments (Interface ST7735 SPI display)

Introduction

• Nuvoton NUC980  is a 300 Mhz ARM processor.
• Has a host of peripherals onboard: 64/128 MB RAM, 2 Ethernets, 2 CAN masters, some 8 UARTS, SPI, I2C , etc
• It comes with Linux, uboot and a buildroot system for generating system assets.
• A popular board is the NUC980 IIOT board
• The major advantage is that this processor is available for a low cost of 5$ (2021)

Intention

• Try and see how fast the system is
• Performance of python etc.
• Given that it was a low RAM system, how convenient would it be write a program in python.
• Maybe interface a device say a Display.

Experiments

• The tar ball that Nuvoton provides is an approx 8 GB virtual machine running Ubuntu 18.04.
• One can run this virtual image on an VM emulator.
•  The recommended is VMWARE but it ran comfortably even in an Oracle VirtualBox VME.
• After logging into the VM and on running a make nuc980_defconfig it generated the uboot, linux and other assets.
• On Linux one can use nuwriter to flash the SPINAND. 
• A run.ini file is needed as configuration to the nuwriter
• It specifies destination of writing: SPINAND flash, SDCARD, RAM, etc.
• Each destination has section for which the relevant files to be flashed has to be provided.
• One problem that was noticed was that even though the flash writing progressed successfully, the system would display a few bytes as follows:

NUC980 IBR 20180813 

Boot from SPI-NAND

Nand boot!      #S

finish SPI dow&*

Python support

• Idea was to try writing a user space driver for an SPI device like the ST7735 in python
• A python driver for Pimoroni displays can be found.
• It was modified to drive a color display to show time.
• Python took a long time loading but after it was loaded in RAM, it was fast enough to update the display
• Also FB-TFT could have been a good way of interfacing the display
• Below are 2 sample videos.