?


Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

On 2017-10-12 11:40, Matthijs van Duin wrote:

On Thu, Oct 12, 2017 at 09:07:55AM +0300, Peter Ujfalusi wrote:

quoted

I don't see much benefit of using McASP on OMAP4, only drawbacks... It
lacks AFIFO so it is prone to underrun and if it underruns you need to
reset McASP. Been there with the Samsung Galaxy Nexus.

AESS/ATC isn't able to consistently respond to a DMA request within 20
us ?  Strange.. I would have expected it to have no trouble with that.
(And presumably so did TI, or they would have included AFIFO?)

quoted

I wonder how Motorola is using the McASP as the OMAP4 version
(officially) does not support I2S.

Hmm? I checked the omap4430 TRM and I don't see that mentioned. It seems
to have pins for i2s transmit:

	abe_mcasp_axr              O     Audio transmit data
	abe_mcasp_aclkx            O     Transmit bit clock
	abe_mcasp_ahclkx           O     Transmit high-frequency master clock
	abe_mcasp_afsx             O     Transmit frame synchronization
	abe_mcasp_amute            O     Mute out to external
	abe_mcasp_amutein          I     Mute in from external

If it supported s/pdif tx only, then all of these except axr would be
useless.

The McASP transmit section uses the S/PDIF industry format, which is
supported by the DIT transfer mode of the module.

And look for Transfer Modes chapter of McSSP in the OMAP4 TRM.

It is DIT only.

Matthijs

- P?ter