topic Re: USB example with external sdram memory with IMXRT1062 in i.MX RT Crossover MCUs

USB with graphical interface with IMXRT1062

marcellocampani — Tue, 28 Jan 2020 15:47:37 GMT

Good morning everyone

I'm using the mimxrt1060-evk

I need to integrate usb host functionality in a design with graphical interface.

To do this I mixed the examples "emwin slide show" and the host_msd_fafts_bm.‌

Because of the memory needed by emwin I need to use the external SDRAM for data.

With this configuration the usb example doesn't work.

To isolate the problem I tried simply to change the memory used by the usb example alone from the default SRAM_DTC to board_sdram moving up this latter to the first position in memory configuration. With this memory configuration the usb example doesn't work anymore. Any suggestion?

Thank you in advance for collaboration.

Re: USB example with external sdram memory with IMXRT1062

jackking — Wed, 29 Jan 2020 16:33:01 GMT

I have a similar question outstanding for both USB host examples and FatFS... so far the only resolution was to place the entire Heap and Stack into a noncached memory section.

I would love to know which control structures for FatFS and USB Host need to explicitly reside in non-cached memory.

Re: USB example with external sdram memory with IMXRT1062

marcellocampani — Thu, 30 Jan 2020 09:25:16 GMT

Hello Mr. King

How did you place the heap and stack in noncached memory? I tried with these settings but the program crashes..

Thank you for collaboration.

Best regards

Re: USB example with external sdram memory with IMXRT1062

jackking — Thu, 30 Jan 2020 17:42:26 GMT

Sorry, it should be the Global Data placement:

Re: USB example with external sdram memory with IMXRT1062

marcellocampani — Mon, 03 Feb 2020 08:22:45 GMT

Hello Mr. King

With global data placement in SRAM_DTC you put ALL the data in that section. the usb works but the emwin graphical interface overflows. Are you using the graphical interface with usb?

Best regards

Re: USB with graphical interface with IMXRT1062

jackking — Tue, 04 Feb 2020 19:44:17 GMT

Sorry, I'm not using emWin, but are you able to place the frame buffer used by emWin into a different memory segment explicitly?

Re: USB with graphical interface with IMXRT1062

marcellocampani — Fri, 07 Feb 2020 08:01:35 GMT

I placed the frame buffer in external SDRAM and now it works correctly.

Thank you for collaboration.