Hi Xavi
for dongles I suggest to work with tech support of dongle vendors,
since they may have to update dongle firmware. Regarding boot on
custom board, if you "don't know what and how", I would highly recommend
to start with Freescale BSPs and probably OBDS (and debugging with jtag if
possible).
L2.6.35_1.1.0_ER_SOURCE
: i.MX28 Linux 2.6.35 Source Code
IMX_OBDS
In particular you need to blow some fuses, please look at Table 12-3. General ROM Bits
i.MX28 RM. You can check fuses on i.MX28 EVK with jtag and OBDS (stmp_otp.c test)
and blow custom board with similar settings.
When you don't have the SD card plugged into the slot (SSP Interface), the debug UART port
comes up with an error code 0x8020a014 which corresponds to "ERROR_DDI_SD_MMC_DEVICE_
NOT_SUPPORTED".
Blow the HW_OCOTP_ROM7 ENABLE_SSP_12MA_DRIVE bit
(to avoid TKT131240 SSP0/1-SD/MMC/eMMC Boot: SSP_SCK polarity setup issue in ROM)
Check fuse SD_POWER_GATE, when CARD_DETECT
goes low due to card insertion, i.MX28 firmware will drive SD_POWER_GATE low to connect
VDDIO_3V3 to VDDIO_SD. Remember to add 10K pull-up resistor on both SSP0_CMD and
SSP1_CMD.
If "HW doesn't uses battery" :
below steps is used to configure the VDD5V power source as DCDC, instead of battery:
1. Generate the bootlet source code:
./ltib –p boot_stream.spec -m prep // generate bootlet source code
2. In imx-bootlets-src-10.12.01/power_prep/power_prep.c:
#define NO_DCDC_BATT_SOURCE // enable VDD 5V only
3. Rebuild the bootlet code:
./ltib -p boot_stream.spec -f //build bootlet code
Since wifi dongles may consume large current, you should check if i.MX28 PMU and
board is able to provide it.
Best regards
chip
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