LMH1218 - SPI Interface connection (Not used in daisy chain)

Kawai

Guru 19775 points

Other Parts Discussed in Thread: LMH1218

Hi Team,

Please allow me to ask you about LMH1218 used in SPI Interface (not used in daisy chain mode).

Generally, I think SPI could use MISO/MOSI/CLK as a common bus line and have separate SS_N for each device.

Regarding the LMH1218 datasheet, MISO pin seems to be a CMOS output.

Do you need to use separate line for MISO as it is not 3-state output ? (Prepare separate input pins for Master device from each LMH1218.)

Best Regards,

Kawai

over 7 years ago

0 Kawai over 7 years ago

Guru 19775 points

Hello,

I found the following description in the datasheet. Does this mean that MISO pin is 3-level output pin ?
I need to make sure that MISO is Hi-Z when SS_N = High.

Best Regards,
Kawai

0 Nasser Mohammadi over 7 years ago in reply to Kawai

TI__Guru* 88905 points

Greetings Kawai-San,

Yes MISO is 3-level output pin. You can setup your devices as noted in the following diagram:

https://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus#/media/File:SPI_three_slaves.svg

Regards,,nasser

0 Kawai over 7 years ago in reply to Nasser Mohammadi

Guru 19775 points

Hello Nasser-san,

Thank you for the answer.
It would be helpful if you could fix the typo in the "Pin Descriptions" section in datasheet page 3, to avoid confusion.

2-Level --> 3-level

Best Regards,
Kawai

0 Nasser Mohammadi over 7 years ago in reply to Kawai

TI__Guru* 88905 points

Sure Kawai-San,

I have made a note to fix this on next revision of the LMH1218 data sheet.

Regards,,nasser

0 Kawai over 7 years ago in reply to Nasser Mohammadi

Guru 19775 points

Thank you, Nasser-san.

Best Regards,
Kawai

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LMH1218 - SPI Interface connection (Not used in daisy chain)