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偶然发现荔枝派V3S上电有概率不能启动TF程序的问题，电源都正常工作。

U-Boot SPL 2017.01-rc2-00075-gec3f3ba-dirty (Dec 15 2017 - 14:00:51)
DRAM: 64 MiB
Trying to boot from MMC1

U-Boot 2017.01-rc2-00075-gec3f3ba-dirty (Dec 15 2017 - 14:00:51 +0800) Allwinner Technology

CPU:   Allwinner V3s (SUN8I 1681)
Model: Lichee Pi Zero
DRAM:  64 MiB
MMC:   SUNXI SD/MMC: 0
SF: unrecognized JEDEC id bytes: 00, 00, 00
*** Warning - spi_flash_probe() failed, using default environment

Setting up a 800x480 lcd console (overscan 0x0)
dotclock: 33000kHz = 33000kHz: (1 * 3MHz * 66) / 6
In:    serial@01c28000
Out:   serial@01c28000
Err:   serial@01c28000

U-Boot 2017.01-rc2-00075-gec3f3ba-dirty (Dec 15 2017 - 14:00:51 +0800) Allwinner Technology

CPU:   Allwinner V3s (SUN8I 1681)
Model: Lichee Pi Zero
DRAM:  64 MiB
MMC:   SUNXI SD/MMC: 0
SF: unrecognized JEDEC id bytes: 00, 00, 00
*** Warning - spi_flash_probe() failed, using default environment

Setting up a 800x480 lcd console (overscan 0x0)
dotclock: 33000kHz = 33000kHz: (1 * 3MHz * 66) / 6
In:    serial@01c28000
Out:   serial@01c28000
Err:   serial@01c28000
Net:   phy interface0
eth0: ethernet@1c30000
starting USB...
No controllers found
Hit any key to stop autoboot:  0
reading zImage
4016104 bytes read in 633 ms (6.1 MiB/s)
reading sun8i-v3s-licheepi-zero-dock.dtb
11803 bytes read in 23 ms (501 KiB/s)
## Flattened Device Tree blob at 41800000
   Booting using the fdt blob at 0x41800000
   Loading Device Tree to 42dfa000, end 42dffe1a ... OK

Starting kernel ...

为何沉鱼落雁的土匪固件运行2次uboot?

diff

phy@01c19400 {
            compatible = "allwinner,sun8i-v3s-usb-phy";
            reg = <0x01c19400 0x00000003 0x6374726c 0x00000008>;
            reg-names = "phy_ctrl", "pmu0";
            clocks = <0x00000002 0x000000a4>;
            clock-names = "usb0_phy";
            resets = <0x00000002 0x000000b7>;
            reset-names = "usb0_reset";
            status = "okay";
            #phy-cells = <0x00000001>;
            usb0_id_det-gpio = <0x00000006 0x00000003 0x00000003 0x00000002>;
            linux,phandle = <0x00000005>;
            phandle = <0x00000005>;
        };
&usbphy {
    usb0_id_det-gpio = <&pio 5 6 GPIO_ACTIVE_HIGH>;
    status = "okay";
};

phy@01c19400 {
            compatible = "allwinner,sun8i-v3s-usb-phy";
            reg = <0x01c19400 0x00000003 0x6374726c 0x00000008>;
            reg-names = "phy_ctrl", "pmu0";
            clocks = <0x00000002 0x000000de>;
            clock-names = "usb0_phy";
            resets = <0x00000002 0x00000133>;
            reset-names = "usb0_reset";
            status = "okay";
            #phy-cells = <0x00000001>;
            usb0_id_det-gpio = <0x0000000b 0x00000003 0x00000003 0x00000002>;gpio?
            linux,phandle = <0x0000000a>;
            phandle = <0x0000000a>;
        };

gpio?

@cube
大师果然名不虚传,一下子就帮小弟出掉bug.

难道usb的5v不是和排针5v一起的?那usb供电也没和usb vcc3.3连接啊.本质 就是usbvcc悬空的?感觉不可思议啊,usb micro mini的5v是没和芯片的vcc usb3.3v连接的,是和排针5v连的,按理说能通过排针5v供电启动,通过usb连接器的5v供电也是能启动的,除非有不可描述的设计,让usb单独供电就不许启动.

到底是什么原因导致直接usb供电就不能开机呢?我直接5v加到5v的排针那里,搜搜就开机了.