audio_loopback Directory Reference

Directory dependency graph for audio_loopback:

Directories
	src

Detailed Description

Pushes stereo PCM to the EK-RA8D2's on-board DA7212 CODEC over SSIE0, driven entirely through the board layer's audio bring-up rather than a hand-rolled SSIE sequence. Sound comes out of the AUDIO OUT jack.

Never verified end to end on silicon: it builds, and the CODEC pin routing matches the board manual, but nobody has heard it. The main loop also feeds silence – the "loopback" in the name is a holdover from an earlier hand-written SSIE test and the app is playback-only. Swap the silence buffer for a sine table to hear anything.

J41 must be jumpered for the CODEC. Two of the CODEC's SSIE data pins are shared with the parallel-camera data lines, so the board wires them to one peripheral or the other, never both. If the camera is fitted, this app is mute by construction.

When it does get bench time, the SSIE status register's overrun and underrun flags are the first thing to read: a starved or over-fed FIFO is the usual reason a correct-looking bring-up produces nothing.

Pin assignments follow EK-RA8D2 v1 UM Table 32 "Audio CODEC Port Pin Assignments" p 38 and Section 6.6; the peripheral is HUM R01UH1065EJ0130 Ch 46 "SSIE".