DM8148 McBSP not able to configure the registers?

Tianhua Chu

Other Parts Discussed in Thread: DM3730

I am using DM8148 EVM and the McBSP is not connected to anything, even I have configured McBSP Pin Mux properly.

I just want to have a dlb or alb enabled for a loopback test.

But I found I am not able to configure the McBSP registers, e.g., set RCR2 (0x47000018) to 0x80A1, but RCR2 is still a "0" value not changing. When I set SPCR2 (0x47000010) to 0x230, it shows 0x210. and so forth.

Is there any extra steps to enable McBSP, in addition to McBSP clock setup from PRCM?

And, I did not find this DM8148 McBSP support from Linux PSP of sdk_5_00_26.

Thanks in advance,

Philip

over 15 years ago

0 David Friedland over 15 years ago

TI__Mastermind 18320 points

Philip,

Your issue seems to be related to direct use of the McBSP, so I have moved this thread to the appropriate device forum in hopes that it will get a faster response there.

Dave

0 Tianhua Chu over 15 years ago in reply to David Friedland

Intellectual 560 points

Thanks Dave.

Anybody to give some suggestions?

Philip

0 Tianhua Chu over 15 years ago in reply to Tianhua Chu

Intellectual 560 points

Anybody???

Philip

0 Brad Griffis over 15 years ago in reply to Tianhua Chu

TI__Guru*** 125430 points

Are you making 16- or 32-bit register accesses? I don't see a specific requirement listed in the DM8148 TRM, but in the past (e.g. DM3730) the McBSP required all register accesses to be performed as 32-bit accesses. It's not intuitive since only the bottom halves of the registers appear to be used. So make sure you're using the proper data type for your pointer in order to always perform 32-bit accesses.

0 Tianhua Chu over 15 years ago in reply to Brad Griffis

Intellectual 560 points

Thanks Brad.

I am using 32-bit register accesses for McBSP and other devices on DM814x.

And also, do you have any samples to use McBSP on DM814x?

Regards,

Philip

0 Brad Griffis over 15 years ago in reply to Tianhua Chu

TI__Guru*** 125430 points

Tianhua Chu said:
And also, do you have any samples to use McBSP on DM814x?

Are you looking for Linux drivers or low level code? If you're looking for low-level code examples then it will be a few more months.

0 Tianhua Chu over 15 years ago in reply to Brad Griffis

Intellectual 560 points

I don't see this DM8148 McBSP support in Linux driver PSP 5.26 either? Can you show me if you have it ready?

My question still is, why some of the McBSP registers does not allow to be changed?

Thanks,

Philip

0 Brad Griffis over 15 years ago in reply to Tianhua Chu

TI__Guru*** 125430 points

Philip,

I've done some quick experimenting on my board and I see the exact same behavior as you describe. I'm looking closely at the registers and the default values of the various registers do not line up with what I see in a memory window. It seems like the base address is not actually 0x4700_0000 for the McBSP. Specifically, the reset value for SRGR2 = 0x00002000 and the reset value for SRGR1 = 0x00000001. Those registers are supposedly located at addresses 0x4700_0028 and 0x4700_002C. However, looking in my memory window I see those exact values located at addresses 0x4700_0128 and 0x4700_012C. So in a nutshell, I believe that the base address needs to be treated as 0x4700_0100 instead of 0x4700_0000. Go with that for a bit and I bet you'll start having some success. I'll see if I can get someone else to comment.

Best regards,
Brad

EDIT Dec 21, 2015: The documentation has been updated (years ago), but not in the way described here. The base address of the McBSP (in the data manual) has been kept at 0x4700_0000. Instead, the offsets have been changed in the McBSP chapter of the TRM. So for example, the SRGR2 register in the current TRM has an offset of 0x128, but at the time of this discussion the documentation showed an offset of 0x28.

0 Viet Dinh over 15 years ago in reply to Brad Griffis

TI__Genius 15310 points

Brad is corrected (thanks for letting us know). The base address for McBSP is 0x4700_0100, not 0x4700_0000. We will fix this in next DS release. BR, Viet

0 Tianhua Chu over 15 years ago in reply to Brad Griffis

Intellectual 560 points

Thanks very much for your help Brad.

I changed the starting address and now everything works very well.

Best regards,

Philip

0 Brad Griffis over 15 years ago in reply to Tianhua Chu

TI__Guru*** 125430 points

Philip,

I'm very glad to hear it's working now! I appreciate your letting us know. Thanks for your patience as we figured out the issue and I apologize for the typo in the data sheet.

Best regards,
Brad

0 hb chen over 13 years ago in reply to Brad Griffis

Expert 2640 points

Dear Brad,

Can you share the code how to enable McBSP loopback testing in dm8148 linux kernel ?

Is the McBSP linux low level driver code ready now ? I want to use McBSP as serial port.

McBSP driver seems not ready in 8148 ezsdk5.

thx ~

0 ranchu over 9 years ago in reply to hb chen

Guru 20755 points

Hello,

I also have issues with mcbsp. Even with polled mode it keeps waiting for regitter values to change.
Can anyone share solution ?
What might be the problem in my case ?

Regards,
Ran

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DM8148 McBSP not able to configure the registers?