Hi Oleg, See inline [DBS]
David -----Original Message----- From: Oleg Evseev [mailto:ev.m...@gmail.com] Sent: Tuesday, November 24, 2020 9:46 AM To: dev@nuttx.apache.org Subject: Re: STM32F4 SPI DMA buffer size issue > Have you scoped the interface? You mean a bus by analyzer? No, I don't have such ability for now. [DBS] Use an oscilloscope, but with a high speed FET probe. You may see incredible overshoot, when DMA is on. For SD card I tried to reduce the SPI frequency from 24MHz to 10MHz, but it didn't help when DMA is enabled. In fact it get failed to find a valid boot record, while fat_hwread of sector zero is returned without errors. [DBS] By drive strength I mean the slew rate control not frequency See https://github.com/PX4/PX4-Autopilot/blob/master/boards/px4/fmu-v6x/nuttx-config/include/board.h#L411-L431 For an eample. The other strange thing I found out, is that when *DMA is not used*, SD can't be used after mounting on boot. If I go through breakpoints in stm32 spi_setfrequency for example it get mounted ok and ls shows SD content. It's hard to understand what is going on because it seems that debug influence on the result. While debugging I saw the case when SD get mounted but than on mkdir of log folder reading mmcsd_geometry get failed in mmcsd_getcsd or mkdir success, but log dir is the only one thing on SD while it is not empty. In this case (without DMA) reducing SPI frequency from 24MHz to 20MHz seems to fix the problem (but maybe it depends on delays and may appear again once there will be more commands on boot for instance, I don't know). Quite a strange behaviour for now. вт, 24 нояб. 2020 г. в 17:12, David Sidrane <david.sidr...@nscdg.com>: > Oleg, > > Have you scoped the interface? > > For gins and giggles try reducing the SPI clock drive strength. Step it > down > and retest. > > David > > -----Original Message----- > From: Oleg Evseev [mailto:ev.m...@gmail.com] > Sent: Tuesday, November 24, 2020 4:57 AM > To: dev@nuttx.apache.org > Subject: STM32F4 SPI DMA buffer size issue > > Hi all, > > STM32f405rg custom board - MTD on SPI1 and SD card on SPI2. > > MTD on SPI1 works without DMA and with if defined CONFIG_STM32_SPI1_DMA=y > > but if also > CONFIG_STM32_SPI1_DMA_BUFFER=1024 > is set, partitions get created, there are mtdblockX in /dev, geometry can > be read correctly, but reading or writing hangs up. > As I see in map g_spi1_rxbuf, g_spi1_txbuf are in SRAM, not in CCM. > > Same with SD card. If defined CONFIG_STM32_SPI2_DMA_BUFFER=1024 there is > still /dev/mmcsd device, it gets mounted, but ls /fs/microsd shows no SD > content. > > CONFIG_STM32_SPI_DMATHRESHOLD=8 > > What can be a problem? Thanks in advance for help! > > --- > With regards, Oleg. >
