User Manual

14. Booting from 64KB SPI flash
The 64K Byte SPI flash is a cost reduction version of booting from flash mode. The small size of
SPI flash is required to store only the mini-uboot with tftp client feature, calibration data and a
small file system. The external host processor will be required to use its flash memory to store
the uboot and linux image for this module. Besides, it will be allowed to control the boot up
sequence of the target by controlling the hardware reset to the module via pin 44 ~HRST. When
the hardware reset is released, the mini uboot will decompress itself into the internal SRAM of
QT3840BC and then start the tftp client to download the full uboot code and linux image from
external processor via xMII bus to the DDR3 memory of the target. Both target and external
host will need IP addresses for the tftp procotol to work. After the linux kernel is boot up, the
system looks the same as booting from the big flash mode.
Note: The RF calibration of the QTM840 chipset is required for on each target board and it is
executed internally but requires the external calibration software to control DUT and the
Litepoint equipment via telnet session. For any system with external host processor, ethernet
bridge between external ethernet port to wifi ethernet port is needed to bridge the RF
calibration control packets to the QT3840BC.
PC: 1.1.1.1
Ethernet
Host:1.1.1.0
QT3840BC:
1.1.1.2
RGMII