The purpose of this document is to communicate known issues with the FRDM-KW41Z development platform. This document applies to all revisions of the FRDM-KW41Z development platform. However, items are divided among their respective revisions and each item may or may not apply to all revisions.
The known issues, which may cause confusion for new customers, for revision A are as follows:
Issue: Jumper, J24, shunt connector does not shunt pins 1 and 2, as noted in the schematic notes.
Impact: Customers will not, by default, be able to put the OpenSDA circuit into bootloader mode.
Workaround: There is currently only one workaround for this issue.
Issue: In certain situations, the serial to USB bridge portion of the default OpenSDA application may not correctly forward serial data. This problem typically only occurs after a POR of a development platform.
Impact: Customers may experience data loss when using the serial to USB converter functionality in their application.
Workaround: There is currently one workaround for this issue.
Issue: When configured for buck mode operation and J8 does not have a shunt connector, it is expected that P3V3_BRD will not be powered and thus, board peripherals will not be powered (thermistor, I2C line pull-ups, SPI Flash, Accelerometer, etc,). However it should be noted that in this configuration, P3V3_BRD will be back-powered through resistor R90. R90 is a 180kOhm resistor that connects directly to the MCU reset pin. This R90 also connects to V_TGTMCU which is directly connected to P3V3_BRD through shorting trace SH500. The internal pull-up on the reset pin will, in this case, power P3V3_BRD.
Impact: Customers will not be able to isolate the MCU IDD current from the board peripherals when measuring current in the buck mode configuration. This is a problem mostly when attempting to achieve datasheet IDD current numbers for low power modes in buck mode.
Workaround: There are currently three (3) workarounds for this issue.
Issue: The signal SWD_CLK_TGTMCU is incorrectly routed to pin 1 of connector J12 instead of pin 4 of the SWD connector, J9.
Impact: With this routing, when the OpenSDA circuit is configured as a stand-alone debugger for debugging other targets (i.e., when J12's shorting trace is cut), the OpenSDA SWD clock will not be able to be present on pin 4 of connector J9. Therefore, the FRDM-KW41Z cannot act as a stand-alone debugger to facilitate debugging other systems.
Workaround: There is currently only one workaround for this issue. The workaround is a hardware workaround that requires a cutting tool (such as a modeler's knife), soldering iron, solder, and a spare wire. To implement the workaround, follow these instructions.