Cirrus Logic Lochnagar-2 with "Hillside" WM8998 Codec Eval Miniboard

I’m using the Cirrus Logic part #CDB6271-2, Lochnagar-2 CODEC Evaluation Main Board, Digikey part #598-2451-ND, with the WM8998 CODEC Audio Evaluation Board, part #CDBWM8998-M-1, Digikey part #598-2408-ND for an audio muxing/mixing product. Though the Lochnagar board is recognized and configurable by WISCE, the Hillside board is not. Are there any configuration options that should be applied to make the Hillside/WM8998 visible on the SLIMBUS?



I don’t know of anyone here having personal familiarity with this particular tool ecosystem (I claim none) so asking Cirrus may garner better-informed responses.

That said, page 58 of the Lochnagar user guide includes the following:

If I interprassume correctly, you’ve got the '8988 board stuck on the Lochnagar, which is USB’d to a PC running the WISCE suite, and you’re trying to chat over the SLIMBUS to the '8988 via the USB connection. It would appear that this is not natively supported by the Lochnagar per the above. I’d assume that interfacing with the ‘8988 via USB by some other route would be possible, but I’d need more than 30 minutes’ familiarity with the ecosystem to provide any useful guidance toward that end.

Hi Rick,

Thanks for the reply, and I truly appreciate your help. I’ve read that paragrah and I considered it, along with other published information, ambiguous. Also, it appears that the Lochnagar 2 supports I2C over USB as that is the interface/protocol used to communicate between WISCE on a PC. In my original posting I referenced SLIMBus mistakenly, as the WISCE GUI specifies SMBUS as the control interface for both the Lochnagar 2 and the WM8998 miniboard. That said, the WM8998 should be visible on I2C at address 0x34 or 0x36. Queries to those addresses fail with a “WMS_COMMS_NO_ACK” error. Access to the Lochnagar 2 board work fine. Are there jumper or switch settings on either board that enable I2C communications for the WM8998 Hillside miniboard?


I’ve found little mention of hardware jumpers in the documentation that appears relevant; it seems likely to be a soft configuration setting that’s amiss. I’m likely to be of little help on that front, again due to lack of familiarity.

I’d point out though, that the '8988 appears to be end of life per this page, with WM8904 the suggested replacement. I’m seeing a last time buy date about 7 weeks from now, so if you’re looking at any sort of production beyond the dev tools in your hand, it’d seem prudent to look at some other codec.

Hi Rick,

Thanks for the info. I’ve corrected the problem, which was the order in which the various VDDs were turned on. The device we are using is the WM8998, not the WM8988. It is not on the EOL list as of yet. This phase is a proof of concept, and we’ll move to a Cirrus part with a DSP onboard for future development and/or productization.