i.MX Processors中的主题 Re: IMX535 and DDR3, needs pull ups?

IMX535 and DDR3, needs pull ups?

sherry_zahid — Thu, 08 Oct 2015 13:38:09 GMT

Hi,

Just wondering if I need any external pull ups on the data and address lines when interfacing the IMX535 with DDR3 modules (Micron MT41K512M16). Also, on page 153 of the Datasheet for the IMX535 it shows a table with "out of reset conditions" for all the IO pins (for the address and data bus for DDR3). For example it states for the pin "DRAM_A0" a config value of "LOW", does this mean no internal pull up is enabled or present on this line during reset? Thank you for your time and help.

Re: IMX535 and DDR3, needs pull ups?

igorpadykov — Fri, 09 Oct 2015 01:47:55 GMT

Hi Sherry

external pull ups are not needed, for connections example

one can look at

MCIMX53-START i.MX53 QS Board Schematics (REV 3)

i.MX53 Quick Start Board|Freescale

For "DRAM_A0" page 153 of the Datasheet meaning is that pull up is disabled.

Best regards

igor

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Re: IMX535 and DDR3, needs pull ups?

sherry_zahid — Fri, 09 Oct 2015 12:49:30 GMT

Hi Igor

Thanks for your reply. I also meant to ask, would there be any design violations if I tie all of the following ground pins together and route them to ground without any external pull resistor?

A1, A11, A13, A18, A2, A22, A23, AA11, AA15, AA20, AA21, AB1, AB18, AB2, AB22, AB23,

AC1, AC18, AC2, AC22, AC23, B1, B11, B13, B18, B23, C12, C20, C21, D19, E19, F19, F20,

F21, F22, G19, G7, H10, H12, H8, J11, J13, J15, J17, J20, J9, K10, K12, K14, K16, K21, K8,

L11, L13, L15, L7, L9, M10, M12, M14, M16, M8, N11, N13, N15, N9, P10, P12, P14, P16,

P21, P7, P8, R11, R13, R15, R17, R20, R9, T10, T14, T16, T8, U15, U19, V15, V18, V19,

V20, V21, V22, W19, Y14, Y15, Y19

Thanks again!

Re: IMX535 and DDR3, needs pull ups?

igorpadykov — Mon, 12 Oct 2015 01:52:25 GMT

Hi Sherry

no problem with such connection.

Best regards

igor

Re: IMX535 and DDR3, needs pull ups?

sherry_zahid — Mon, 12 Oct 2015 17:21:17 GMT

Thank you very much Igor, your prompt help and support is much appreciated.

Kind regards,

Sherry