https://community.nxp.com/t5/i-MX-Processors/Uboot-too-fast-and-USB-host-read-timeouts/m-p/498250#M80349 <HTML><HEAD></HEAD><BODY><P>We made a small production serie of 10 PCBA's with a i.MX6D based on a custom design.</P><P>This board has a dedicated USB host (i.MX6 host port) and USB device (i.MX6 OTG port) connection.</P><P>9 boards are working fine, but on one board we see 3 problems:</P><OL><LI>uBoot seems to run faster than on the other boards, about 3 times faster.</LI><LI>After a cold start the USB stick at the USB host port of the i.MX6 is not always recognised.</LI><LI>When the USB stick do get recognised, we get read timeouts when we try to access the data.</LI></OL><P></P><P>Problems 1 and 2 seems to be dependant on the board temperature. When the temperature rises, uBoot seems to slow down a bit, but still faster than on the other boards. The USB stick now gets recognised all the time. But still read timeouts.</P><P></P><P>Things I have checked:</P><UL><LI>24MHz crystal is stable and at the right frequency, at cold startup and after couple hours.</LI><LI>Power supplies are all in the right range and ripple is less than 5%.</LI><LI>I saw that the LDO_2P5 had a saw tooth voltage ripple which was near 5%. Followed the EB814 document on minimum ESR requirements, placed a 100mOhm resistor is series with the bulk capacitor of de LDO_2P5 regulator. The saw tooth voltage ripple disappeared. But no change in the behaviour of the board.</LI><LI>No USB problems detected on the i.MX6 OTG port in device mode</LI></UL><P></P><P>I am out of ideas now, so if any of you have suggestions, please let me know.</P></BODY></HTML> Tue, 01 Mar 2016 09:27:32 GMT thomaslantinga 2016-03-01T09:27:32Z https://community.nxp.com/t5/i-MX-Processors/Uboot-too-fast-and-USB-host-read-timeouts/m-p/498250#M80349 <HTML><HEAD></HEAD><BODY><P>We made a small production serie of 10 PCBA's with a i.MX6D based on a custom design.</P><P>This board has a dedicated USB host (i.MX6 host port) and USB device (i.MX6 OTG port) connection.</P><P>9 boards are working fine, but on one board we see 3 problems:</P><OL><LI>uBoot seems to run faster than on the other boards, about 3 times faster.</LI><LI>After a cold start the USB stick at the USB host port of the i.MX6 is not always recognised.</LI><LI>When the USB stick do get recognised, we get read timeouts when we try to access the data.</LI></OL><P></P><P>Problems 1 and 2 seems to be dependant on the board temperature. When the temperature rises, uBoot seems to slow down a bit, but still faster than on the other boards. The USB stick now gets recognised all the time. But still read timeouts.</P><P></P><P>Things I have checked:</P><UL><LI>24MHz crystal is stable and at the right frequency, at cold startup and after couple hours.</LI><LI>Power supplies are all in the right range and ripple is less than 5%.</LI><LI>I saw that the LDO_2P5 had a saw tooth voltage ripple which was near 5%. Followed the EB814 document on minimum ESR requirements, placed a 100mOhm resistor is series with the bulk capacitor of de LDO_2P5 regulator. The saw tooth voltage ripple disappeared. But no change in the behaviour of the board.</LI><LI>No USB problems detected on the i.MX6 OTG port in device mode</LI></UL><P></P><P>I am out of ideas now, so if any of you have suggestions, please let me know.</P></BODY></HTML> Tue, 01 Mar 2016 09:27:32 GMT https://community.nxp.com/t5/i-MX-Processors/Uboot-too-fast-and-USB-host-read-timeouts/m-p/498250#M80349 thomaslantinga 2016-03-01T09:27:32Z https://community.nxp.com/t5/i-MX-Processors/Uboot-too-fast-and-USB-host-read-timeouts/m-p/498251#M80350 <HTML><HEAD></HEAD><BODY><P>Hi Thomas</P><P></P><P>one can attach jtag debugger or using uboot commands and output</P><P>arm clock on CCM_CLKO1,2. Program CCM_CCOSR register </P><P>and measure frequency arm_clk_root, osc_clk. In general chip</P><P>can be damaged due to ESD or overheating.</P><P></P><P>Best regards</P><P>igor</P><P>-----------------------------------------------------------------------------------------------------------------------</P><P>Note: If this post answers your question, please click the Correct Answer button. Thank you!</P><P>-----------------------------------------------------------------------------------------------------------------------</P></BODY></HTML> Wed, 02 Mar 2016 01:40:54 GMT https://community.nxp.com/t5/i-MX-Processors/Uboot-too-fast-and-USB-host-read-timeouts/m-p/498251#M80350 igorpadykov 2016-03-02T01:40:54Z