15-08-2015, 21:22
OK, here are more traces from the scope. Channel 1 (yellow) is on the nano; channel 2 (blue) is at the header for the display. All are at 2 volts/div vertical; horizontal is 1 uS/div except for the DC trace, which is 5 uS/div.
CS10 (pin D10 on the nano):
MOSI (pin D11 on the nano):
SCK (pin D13 on the nano):
DC (pin D6 on the nano):
What I'm noticing on these: MOSI, SCK, and DC show expected levels with good rise and fall. Ch2 (the output of the level shifter) is showing greater over- and under-shoot than Ch1. CS10, though, is showing much slower rise/fall, and the output of the level shifter is still 5 volts peak-to-peak. I'm not sure if this is what's supposed to happen, but it isn't what I'd expect.
CS10 (pin D10 on the nano):
MOSI (pin D11 on the nano):
SCK (pin D13 on the nano):
DC (pin D6 on the nano):
What I'm noticing on these: MOSI, SCK, and DC show expected levels with good rise and fall. Ch2 (the output of the level shifter) is showing greater over- and under-shoot than Ch1. CS10, though, is showing much slower rise/fall, and the output of the level shifter is still 5 volts peak-to-peak. I'm not sure if this is what's supposed to happen, but it isn't what I'd expect.