5409, McBSP hardware loopback

Leonard Jowers86084

Intellectual 650 points

5409, I’m implementing an RS-232-like programmed-I/O (not DMA) through McBSP1.

Transmit seems to work fine.

I’ve connected BDX and BDR (and out to RS-232 port on a PC ).

My PC displays the data but I never get MC_BSP_READY from SPCR11.

Can you tell if I have something set up wrong?

McBSP1
SPCR11	0003
SPCR21	02C3
RCR11	0040
RCR21	0001
XCR11	0040
XCR21	0001
SRGR11	0081
SRGR21	2000
MCR11	0000
MCR21	0000
RCERA1	0000
RCERB1	0000
XCERA1	0000
XCERB1	00FF
PCR1	0F00

over 9 years ago

0 Sivaraj Kuppuraj over 9 years ago

TI__Mastermind 35645 points

Hi,

Team will work on this and will provide an update on this request.

Thanks & regards,

Sivaraj K

0 Steve Tsang over 9 years ago

TI__Mastermind 23785 points

First of all, SPCR11 = 0003, thus bit 1 RRDY is 1. Next, try disables SPCR2:FREE bit; SRGR1:CLKGDV is 81, double check your sample-rate frequency; try SPRGR2:FREE mode; why XCERB is 00FF? Are you using FSX, CLKX, FSR and CLKR as serial operations?

Regards.

0 Leonard Jowers86084 over 9 years ago in reply to Steve Tsang

Intellectual 650 points

Thank you (I’ve been out of town and unable to check things).

Yes, SPCR11 is 0003 on initialization and there is an extraneous NULL character that I read.

I transmit at 38400 (CLKMD=0, to use ½, disabled PLL) and receive the correct characters on a PC.

I do not know how I recorded 00FF for XCERB L; I rechecked and it is 0000 (as the others are).

As you suggested, I tried SPCR2:FREE disabled but saw no difference (except for SPCR2 content).

With respect to FSX, CLKX, FSR and CLKR, I am setting the PCR to 0F00 (I have also tried 0B0C because I suspect that is where my error is; no difference). I am wanting to use the 5409 clocks.

External to the 5409, I only have BDX and BDR connected (and both to Rx to the PC).

I appreciate your trying to help me.

0 Leonard Jowers86084 over 9 years ago in reply to Leonard Jowers86084

Intellectual 650 points

More information: I enabled Digital Loopback and receive data that matches what I transmitted.

0 Steve Tsang over 9 years ago in reply to Leonard Jowers86084

TI__Mastermind 23785 points

Great! Problem solved. Please close this posting for closure.

Regards,

0 Leonard Jowers86084 over 9 years ago in reply to Steve Tsang

Intellectual 650 points

? Not solved. With digital loopback off, I do not receive anything. I need to show a wire loopback to presume that I can receive data.

0 Steve Tsang over 9 years ago in reply to Leonard Jowers86084

TI__Mastermind 23785 points

1. SPCR11 is 0003 on initialization is incorrect. It should be all 0000. RRDY = 1 means there are receiving data in DRR[1,2].

2. With loopback on, it works. Basically it means your programming to receive is correct. Can you scope signals on receiving pins to confirm PC sends back data.

Regards.

0 Leonard Jowers86084 over 9 years ago in reply to Steve Tsang

Intellectual 650 points

Thanks for hanging in there with me. I scoped the board and found the signal to the chip was good, so I likely hosed BDR on the processor. If Digital Loopback is sufficient to say that setup is correct, I'm done until I get that resolved.

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5409, McBSP hardware loopback