I'm trying to use FLIR Lepton 3 module with Raspberry Pi 0 W board running Raspbian 9 Stretch. I followed all official FLIR recomendations: connected Lepton module to Raspberry in the correct way (SPI0 port, CE0 as CS pin). I2C and SPI busses have been enabled trough raspi-config. I'm trying to use raspberrypi_video application from this (official) repository:
Everything complied correctly after installing all required libs and after a little rework to adapt the code to the Lepton3 module (different picture size among other) I can see frames coming out but the rate is poor (well below 9Hz .. more probably 0.25 Hz) picture looks like is dived in 4 bands and mixed in the wrong order or taken with a different timing (attached a sample)... I think is some kind of problem of SPI bandwidth or loss of synchronization. The application is not reporting any error/exception during execution.
I tried also with more Lepton3 specific code without more luck (same issues). I tried also changing CE0 with CE1 (and changing spi device code accordingly) without any positive effect as it was obvious.
Someone tried succesfully the same configuration? I know someone did since there's a video of my same configuration running fine:
Of course I tried the code reported along youtube video but the result is always the same (except for the color palette).
I had no issues using the same configuration on Raspberry Pi 3 B+, video frames are played at the maximum rate (~9Hz) without any visible artifacts.
I don't think it's a problem of hardware resources since top CPU load during my test on RPi0W was never over 30%. Of course I tried with a different RPi0W unit without any appreciable difference.
I found a partial fix adding
spidev.bufsiz=131072 sentence to /boot/cmdline.txt (thnx to Luke Van Horn) now the image is not splitted in 4 bands (maybe they are just 2 but more in synch) but the frame rate is still poor (0.5 - 0.25Hz).