Ok, thanks for your help, I finally got it. My SYS_BOOT configuration was wrong: I inserted also the "do not insert" resistors. After removing them the card module worked and I was able to boot. The 0.5V is the voltage that you can measure in a pin that has an active pull-down: after fixing the SYS_BOOT the OMAP tried to boot from mmc and it disabled the pull-downs in the mmc pins before attempting to boot from card.
El martes, 25 de marzo de 2014 23:01:33 UTC+1, 4ndr...@gmail.com escribió: > > Hello, I built a board really similar to beagleboard rev4 from scratch. I > just added some USB ports and other few changes.(buy the components, > manufacture it, design the layers..etc) > After some problems I finally got a “40W” in the terminal connected to > UART3. I could not boot from SDCard because, despite the voltage in VMMC1 > is 3V, my WP, DAT[3-0] and CMD pins have a strange voltage value. The > voltage values measured in the SDCard reader are shown in this table: > > MY BEAGLE ORIGINAL BEAGLE 0.5 V 1.8 V WP Conected to OMAP 1.8 > V 1.8 V CD Conected to TPS65950 0.51 V 3 V DAT1 Conected to OMAP 0.507 > V 3 V DAT0 Conected to OMAP 0 V 0.078 V DAT7 Conected to OMAP Powered > by VSIM 0 V 0 V GND 0 V 0.072 V DAT6 Conected to OMAP Powered by VSIM > CLK Conected to OMAP 3 V 3 V VDD 0 V 0 V GND 0 V 0.072 V DAT5 > Conected > to OMAP Powered by VSIM 0.5 V 3 V CMD Conected to OMAP 0 V 0.073 V DAT4 > Conected > to OMAP Powered by VSIM 0.513 V 3 V DAT3 Conected to OMAP 0.507 V 3 V > DAT2 Conected to OMAP > > After check the voltages in a real beagleboard I found that DAT[0-3] and > CMD are 3V. I have been searching a lot but I could not find why my voltage > values are wrong. > > The hardware configuration is the same as the original beagleboard: to > power OMAP3530 I am using TPS65950. The only difference is that due to a > design fail I needed to cut the connection of VMMC1 with the TPS65950 and I > am powering VMMC1 with an external source (3V). I took care of give power > to VDD in the card reader and to VDDS_MMC1 in the OMAP3530. > > VSIM is 0V after reset despite VAUX12S is powered at 3.6V. I could not > load any loader into the board yet. If I can not fix MMC problems I will > try to boot from UART, because of the 40W it seems that the OMAP processor > is alive. > > Really thanks. > > PD: > > 1) Because all the wrong voltages in my board are almost the same value > (0.5 V) I thought that maybe the original beagleboards comes with a > different preconfigured pins state-after-reset (pull-down or something) > than the OMAP3530 bought directly??? > > 2) Can I say that VMMC1 is reaching correctly the VDDS_MMC1 pin in the > OMAP3530 because of the 0.5V in the pins? or the connection between VMMC1 > and VDDS_MMC1 could be cut despite the 0.5V? > > > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
