AM5728: 8-bit data access to PCIe mapped domain

shigehiro tsuda

Part Number: AM5728

Hi,

Does the 8bit read access of memory mapped in PCIe of AM5728 support it?
Environment
AM5728 :RC
External device: EP
It has been mapped with DDR3 memory region.

① 0x0102_0304_0506_0708_090A
When it is read the data written in the memory mentioned above by 8bit read access, it is read as follows.
② 0x0100_0000_0500_0000_0900

When I read by 32bit read access, normal data ① is readable.

Best Regards,
Shigehiro Tsuda

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

The PCIe experts have been notified. They will respond here.

0 lding over 9 years ago in reply to Biser Gatchev-XID

TI__Guru* 95265 points

Hi,

No, it doesn't support 8-bit read. You may look at the xillybus.com/.../pci-express-tlp-pcie-primer-tutorial-guide-1 for the PCIE TLP structure for read completion packets.

You can apply a mask 0xFF_00_00_00 to the read back data to get only 8-bit results.

Regards, Eric

0 shigehiro tsuda over 9 years ago in reply to lding

Mastermind 9490 points

Hi Eric,

Thank you for quick reply.
I understood the PCIe of AM5728 doesn't support 8-bit read.

Best Regrads,
Shigehiro Tsuda

0 shigehiro tsuda over 9 years ago in reply to lding

Mastermind 9490 points

Hi Eric,

Thank you for your kindly and quick support.

There is an additional question.
Dose it support 8-bit and 16-bit write ?

Best Regards,
Shigehiro Tsuda

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AM5728: 8-bit data access to PCIe mapped domain