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c6416 hpi problem : hpi read,hpi not ready.

Started by nudt...@sina.com March 17, 2010
Hi all:
my design is so:On PCB,xilinx FPGA(V5)„ÄĀAltera FPGA(S2),they both connect TMS320C6416 through HPI. when S2 use HPI of TMS320C6416 , pins of V5 associated to HPI of TMS320C6416 are set to float. when V5 use HPI of TMS320C6416 , pins of s2 associated to HPI of TMS320C6416 are set to float.
First ,upon PCB Power on , i don't configure V5 through jtag. and i use S2 to boot dsp through hpi successfully. when dsp is running ,i can read L2 sram through hpi.
But, upon PCB Power on , as long as i configure V5 through jtag, i only can boot dsp successfully. But i cannot read L2 sram through hpi in fix-mode. the problem is : when nHSTOBE is go to low, nHrdy pin is go to high,but don't go back to low. this lead to i can't end read operaion succefully. when this happens,i finds that the value of HPIC is 0x000a000a through CCS by XDS560. This sounds HPI is ready. why the pin of hrdy is keep high? the problem dont always occurs.sometimes HPI is ok, i can read L2 sram.
this problem has troubled me for a long time. has some one can help me ? thanks.

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Nud-

> my design is so:On PCB,xilinx FPGA(V5)Altera FPGA(S2),they both
> connect TMS320C6416 through HPI. when S2 use HPI of
> TMS320C6416 , pins of V5 associated to HPI of TMS320C6416 are
> set to float. when V5 use HPI of TMS320C6416 , pins of
> s2 associated to HPI of TMS320C6416 are set to float.
> First ,upon PCB Power on , i don't configure V5 through jtag.
> and i use S2 to boot dsp through hpi successfully. when
> dsp is running ,i can read L2 sram through hpi.
> But, upon PCB Power on , as long as i configure V5 through jtag,
> i only can boot dsp successfully. But i cannot read
> L2 sram through hpi in fix-mode. the problem is : when nHSTOBE
> is go to low, nHrdy pin is go to high,but don't go back
> to low. this lead to i can't end read operaion succefully. when
> this happens,i finds that the value of HPIC is
> 0x000a000a through CCS by XDS560. This sounds HPI is ready. why
> the pin of hrdy is keep high? the problem dont always
> occurs.sometimes HPI is ok, i can read L2 sram.
> this problem has troubled me for a long time. has some one can
> help me ? thanks.

One guess would be that Virtex 5 config causes HPI pins "move" in some combination that confuses the internal C6416
HPI state machine. For example, HCS goes low and HCNTL0 and HCNTL1 cause HPIA to be written to some value that points
to reserved memory.

One suggestion would be to try a low value pull-up on HCS (say 800 ohm or 1k) and see if that can "protect" HCS during
Virtex 5 config/boot.

-Jeff

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hi jeff,thank you for yuor suggestion!
i follow your suggestion,and the problem have solved!
i have set "nHCS pin of V5" to pull up.(i use IOBUF to implement nHCS pin).and in S2,i also set the attribute 'weak pull-up' to "nHCS pin".
thank you very much!

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