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Host to issue an interrupt to C6415 via PCI

Started by Jay Huang August 23, 2002
Dear DSPers,

I need to design a communication scheme for C6415 to
be able to communicate with a host processor. I am
wondering someone could explain to me how to do this
for C6415 ?

Host
--------
(1) put information to DSP internal memmory.
(2) to generate an interrupt to DSP via PCI port ?

Thank you very much for your information and help.

Sincerely,

Jay Huang



Jay,
If the 6415 uses the same bridge as the 6205 be careful of a potential
race condition. The memory cycle is fifo'ed. The register cycle (to cause
the dsp interrupt), is not.
jrc

John R Campbell
March Networks Corporation
Tower B, Suite 330, 555 Legget Drive
Kanata, Ontario K2K 2X3
T (613) 591-8228 Ext 5809
F (613) 591-3113


Jay,

Basically you need write a host driver to do that.

You can access your DSP target memeory through the
Base Addess 0 space. Also you can use DMA to let C6415
read/write host memory as a PCI bus master. I would
sugguest you use DMA whenever possible because the
host access to DSP may not write to the target
correctly when other PCI activiy is in the bus due to
the problem in c6415's PCI interface.
In order to interrupt the DSP from host, just
write the DSPINT bit in HDCR regiseter through the
Base Address 2 memory. Writing this bit will cause the
HOSTSW interrupt if it is enabled in the PCI interrupt
enable register (PCIIEN).

Regards,
William

--- Jay Huang <> wrote:
> Dear DSPers,
>
> I need to design a communication scheme for C6415 to
> be able to communicate with a host processor. I am
> wondering someone could explain to me how to do this
> for C6415 ?
>
> Host
> --------
> (1) put information to DSP internal memmory.
> (2) to generate an interrupt to DSP via PCI port ?
>
> Thank you very much for your information and help.
>
> Sincerely,
>
> Jay Huang >
> _____________________________________
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__________________________________________________



Hello,

> read/write host memory as a PCI bus master. I would
> sugguest you use DMA whenever possible because the
> host access to DSP may not write to the target
> correctly when other PCI activiy is in the bus due to
> the problem in c6415's PCI interface.

What do you mean with "due to the problem in c6415's PCI interface" ?

Thanks

J-F



Hello,

Please find below the answer that I just got from TI,
to be included in next release of the errata file.

J-F

>> What do you mean with "due to the problem in c6415's PCI
>> interface" ?
>
> Hello,
>
> There is a silicon bug in C6415 PCI interface. TI
> is actually working on it. I did a street test to
> write/read the DSP memory from host using DSP as PCI
> target, the data read back are not exactly same as
> wrote sometimes. The error rate is more than 1% if
> there is other PCI activity on the bus meanwhile.
>
> Regards,
> William
--------------
ANSWER FROM TI
--------------
3 - Silicon Revision 1.03 Known Design Exceptions to Functional
Specifications
and Usage Notes :
3.1 Usage Notes for Silicon Revision 1.03.

PCI: Bursts of 11 Words Sometimes Corrupt Data
On silicon revision 1.03 and earlier, when doing a PCI burst slave
write to the DSP that is 11 words long, the data
may get corrupted. When the data corruption occurs, the eleventh word
of the burst ends up in memory where the
first word goes, and the memory location where the eleventh word
should have gone is left untouched. The data
corruption issue has only been observed in systems where there are
several devices on the PCI bus (for example, a PC).