STM32F746 CubeMX 1.6.0 possible FMC init bug

[Eugene Solo]

Posted on March 07, 2017 at 17:02

I've just assembled and tested (by pin toggling) my custom board.

Initial clock configuration is ok (and I would not recommend using Eclipse plugin, standalone app is way more stable); LED blinker is ok; basic UART configs to see anythiong going from console is ok; now it is time to configure external SDRAM.

I have two 256 Mbit chips in parallel to make 32-bit wide bus - to maximize bandwidth - 64 megabytes total.

As i mentioned before, pin toggle test found no electrical problems - no short or open circuits.

Initial board code is made with help of STM32CubeMX and here is the trouble: pinout, timings and all such things are fine, but default code  is NOT enabling SDCLK (which is mapped to PG8, ofc).

When I've added line

FMC_Bank5_6->SDCMR |= FMC_SDCMR_CTB1 | (1); // MODE : 001: clock Configuration Enable

after timing initialization, clock appeared on that pin and now I see data on bus. SDRAM is still not fully functional because refresh is not set yet.

It seems that code produced by STM32CubeMx is not following the initialization sequence, which is described in chapter 13.7.3 of RM

#stm32cube #bug #stm32f746 #sdram

[Imen.D]

Posted on March 15, 2017 at 14:18

Hello, 

Are you using the latest version CubeMx  v4.20 ?

Imen

[Eugene Solo]

Posted on March 15, 2017 at 17:44

yes, i checked and double-checked.

Manually written code with proper stage sequence is working fine.

[Jeanne Joly]

Posted on January 16, 2018 at 11:07

Hi

Solotchin.Eugene

,

Sorry for the late replay.

I hope that the issue can't be seen on the latest release.

However, if you still encounter the issue, could you please provide more information (MCU serie, line and package you work on and the ioc) in order to have a look in depth to your point?

Thanks in advance.

BR. Jeanne

[Eugene Solo]

Posted on January 16, 2018 at 16:58

I can write test for new release, but currently my board runs on my own firmware, no third-party code except FatFs is involved.

MCU is STM32F746 in PQFP208, two SDRAM chips to make 32-bit wide data bus, 108MHz.

[Jeanne Joly]

Posted on March 05, 2018 at 13:53

Hi

Solotchin.Eugene

,

Which kind of bug do you have on the current release (is it the same as the one reported on the CubeMX4.20?)?

BR. Jeanne

[Eugene Solo]

Posted on March 05, 2018 at 14:28

its some misunderstanding probably.. Currently my board runs my own firmware (written from scratch, based on CMSIS), no CubeMX involved. So I cannot report any cubemx-associated bugs, sorry.

But if you insist, I will download latest release and make some initial code with it, just to test against that odd bug.