spi interface operation

alexander feldman

Other Parts Discussed in Thread: TUSB9261

Hello,

The following question concerns the TUSB9261 usb 3.0 to sata bridge.

I have read the various datasheets and manuals of the device and in those documents it is said that the spi interface can operate over a frequency range 100KHz to 50 Mhz.

1. is the spi operating frequency (SCLK) is determined solely by the usb bridge or is it configureable, if so how?

2. i am especially interested in operating the spi interface at a frequency up to 200 Khz( preferably lower rate) , is it possible?

Regards,

Alexander.

over 13 years ago

0 Elias Villegas M. over 13 years ago

TI__Guru* 76130 points

Hello Alexander,

I apologize for the delay here.

The SPI clock frequency can be adjusted only by firmware.

Tell me your exact requirement and I will pass it to the software team to see if they can release a customized fw.

Regards.

0 alexander feldman over 13 years ago in reply to Elias Villegas M.

Prodigy 50 points

Hello Elias,

I understand that the spi clock frequency is adjustable via firmware. but i belive the initial communication clock frequency is hardware defaulted.

Can you tell what the initial clock frequency is set to? we require a 100 KHz maximum clock frequency (we can stretch our design up to 110 KHz, but it is not advised).

A customized fw would be most appreciated.

Regards,

Alexander.

0 Elias Villegas M. over 13 years ago in reply to alexander feldman

TI__Guru* 76130 points

Hello Alexander,

The SPI clock is fixed in the boot code at 18.75MHz.

Why is your design restricted to 110KHz?

Regards.

0 Brian Quach over 13 years ago in reply to alexander feldman

TI__Expert 4325 points

BootROM is configured for 18.75MHz to read the FW image from SPI flash into RAM.

If you have some other SPI peripherial that is slower, you can change the SPI frequency in FW after it is loaded.

0 alexander feldman over 13 years ago in reply to Elias Villegas M.

Prodigy 50 points

Hello Elias,

I use the same spi flash memory simultaneously for the 2 devices where the usb2sata is one of them. therefore i need the usb2sata spi clock to be considerably slower than the memory's.

the usb2sata boot process is required to be at a rate of 100KHz, is it possible?

I have another question regarding the the fw. does the device read the fw by reading consecutive addresses from memory, or it determines the next address to be read from data that was previously read ?

Regards,

Alexander.

0 Brian Quach over 13 years ago in reply to alexander feldman

TI__Expert 4325 points

Alexander,

BootROM is "ROM" code (read-only) and cannot be changed so no, it is not possible to change the SPI frequency for bootup. SPI FW loading is done by reading consecutive addresses. Base address is sent and then reads are done until data load is complete.

Regards,

Brian

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spi interface operation