I am using the SPX-21316. I’m able to communicate with it using I2C the Qwiic.
The two red power LEDs (Vcc and LED_VIN) light up but the nine other LEDs do not.
When I read the ‘LED TEST CONTROL’ register( 0x41), it shows the D1 to D9 with only 0.052 volts. Vout and Vdd have 3.352 volts.
The AL8860 data sheet says:
“Applying a voltage of 0.2V or lower to the CTRL pin can turn off the output and make the device enter into standby state with low current consumption.”
The 0.052 volts I see is far below the require 0.2 volts.
When I apply 2.5 volts through a 33k resistor to the AL8860 CTRL pin the associated LED lights up.
It appears the LP55231 D1 to D9 pins are not producing high enough voltages.
Hi! Are you running the “Qwiic-visible-spectrum” example code from our LP55231 Arduino library?
That example code calls a new function in that version of the library that puts the LP55231’s integrated charge pump into bypass mode, which is important since we’re not using the charge pump to power the LEDs.
I assume you’re referring to MISC register 36. The software sets this byte to 0x53 or b01010011 where bits [4:3] = 01.
I tried 0x53 but bypassing the charge pump changed my ‘LED TEST CONTROL’ register( 0x41), D1 to D9, voltages to -8 mV from +0.52 volts. A negative voltage doesn’t make sense to me. Figure 25 of the data sheet shows only positive voltages.
To further examine this, I put a For…Loop in my program and ran the program with the MISC register set to every value from 0 to 255. None of the 9 LEDs turned on.
