topic Re: SDRAM AND SDCARD TOGETHER ? in LPC Microcontrollers

SDRAM AND SDCARD TOGETHER ?

lpcware — Wed, 15 Jun 2016 19:13:16 GMT

Content originally posted in LPCWare by manes6969 on Wed May 08 10:37:32 MST 2013

Hi ,

I have succesfully setup the sdram controller to work on the lpc4357 evb from element14. Now i'm trying to get the sdio at work.

The clk for the sdcard is sfclk2. But on this forum I read that all 4 emc clocks are needed for the sdram. And indeed if I use 1 or more clocks for something else like the sdram , then my memory test fails.

So my question , how do you use sdram and sdio at the same time , if all 4 clocks seem to be needed for emc ?

Hoping someone can help me on this

Ronny

Re: SDRAM AND SDCARD TOGETHER ?

lpcware — Wed, 15 Jun 2016 19:13:17 GMT

Content originally posted in LPCWare by manes6969 on Wed May 08 11:16:27 MST 2013

<em>Found the answer !</em>

pin pc0 is also a pin which has a sdio_clk function. Unfortunately this pin is used for lcd (not connected so far).

On the keil mcb4357 board its connected that way ...

maybe i can cut a wire and connect pc0 as clk for the sdio.

Greetings Ronny

Re: SDRAM AND SDCARD TOGETHER ?

lpcware — Wed, 15 Jun 2016 19:13:18 GMT

Content originally posted in LPCWare by Hydron on Wed May 08 17:54:42 MST 2013

You may be able to assign two emc clocks to one pin, to reduce the pins needed from 4 to 2. If you look in the docs, there are two emc clock pins which can be configured as clock 01 and clock 23, I believe if you use them in this configuration it meets the requirements of having all four clocks enabled. Its a weird and annoying design, we spent a lot of time trying to get the ram going before we realised this :(

Re: SDRAM AND SDCARD TOGETHER ?

lpcware — Wed, 15 Jun 2016 19:13:18 GMT

Content originally posted in LPCWare by kjschaefer on Tue Jul 08 07:02:54 MST 2014
The SD slot on the LPC4357-EVB is useless if the LCD or the SDRAM is in operation:

According to the user manual (UM10503.pdf page 578) all four CLKn outputs need to be configured to mode 0 if a SDRAM is used. So the
SD_CLK option for CLK2 can not be used.
The only other option to get the SDIO CLK signal would be Port C pin 0.
But this one is wired to the LCD (LCD_DCLK).

-> No way :-(