1 INTRODUCTION
This guide aims to quickly get U-Boot running on your Renesas RZ/N1S-DB board.
There are several pieces of software that are used to load and run software on the RZ/N1, these
are discussed below. Pre-built binaries are provided to get you up and running quicker.
1.1 Renesas BootROM
The BootROM is internal to the device and is always run on reset. The BootROM loads the first
valid SPKG image from one of three sources, QSPI, NAND or USB DFU, the choice of which is
done via boot mode pins, and starts executing it. DFU is a protocol used with USB to update
software on embedded products; the RZ/N1 device will act as USB Device and is attached to a
USB Host, e.g. a PC.
An SPKG is a Renesas proprietary format that includes information on the size of the binary
payload, the destination for the payload, and optional signature information. For the purposes of
this document, we assume that the device allows SPKGs without a signature.
Note:
The BootROM will only allow an SPKG payload to be written to internal SRAM as writing to
QSPI is board specific.
Normally, on the RZ/N1S-DB board, when the board is reset the BootROM will load an SPKG from
QSPI. Typically, this SPKG contains U-Boot or U-Boot/SPL.
However, by changing the boot mode pins state by holding down a switch when resetting the
board, the BootROM will start in USB DFU mode and will wait for the host PC to upload an SPKG.
1.2 U-Boot
U-Boot is a boot loader that allows you to run commands that can read and write to/from QSPI or
SD cards, load files from a TFTP server, program QSPI using USB DFU, start an OS and start the
Cortex-M3 processor.
Typically, U-Boot will load the Device Tree Blob (dtb) and OS image from QSPI, and pass
arguments to the kernel.
Summary of Contents for RZ/N1S-DB
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