B-Series LED pins' IO Pin Drive Strength

Hardware
#1

Hi There-
I’m designing in the B402 module in a product and had a question about how to configure the off-module status LED and associated current-limiting series resistors which connect to the RED (pin 61) GREEN (pin 63) and BLUE (pin 65) pins of the B-402.

First, are those pins low true when using stock firmware? E.g. should I connect them to the cathode of each LED? I assume that since this LED is used in lower-level firmware indication such as during cell connection and OTA I won’t want to deviate from the standard.

Second, are those pins configured as standard drive (limited to 2mA) or high drive (limited to 9mA)? I’d like to drive the LEDs with a max of 5mA or so, but only if the higher current is supported with stock firmware.

Thanks!
Dave

#2

The RGB pins assume a common anode RGB LED, so yes, the pins connect to the cathode side of each LED and are pulled to GND (not 3V3) to turn the LED on.

The LED pins are standard drive (2mA). The sample design uses larger current limiting resistors to reduce the current and also to reduce the brightness, as most RGB LEDs are blindingly bright at their full design current.

All of the dev kits (such as the Boron) and the B Series evaluation board use 1K current limiting resistors with an RGB LED that is similar to the Cree CLMVC-FKA-CL1D1L71BB7C3C3.

#3

Hi Rick-
This is great, particularly the sample design and documentation. Thank you so much!