RedBoot supports the serial port which is available via a special cable connected to the CON_UART connector on the board. The default serial port settings are 115200,8,N,1. The serial port supports baud rates up to 460800, which can be set using the baud command as described in Chapter 2.
FLASH management is also supported. Two basic RedBoot configurations are supported:
|ROMRAM||[ROMRAM]||RedBoot running from RAM, but contained in the board's flash boot sector.||redboot_ROMRAM.ecm|
|RAM||[RAM]||RedBoot running from RAM with RedBoot in the flash boot sector.||redboot_RAM.ecm|
Since the normal RedBoot configuration does not use the FLASH ROM except during startup, it is unnecessary to load a RAM-based RedBoot before reprogramming the FLASH.
The Portable Demonstration Kit should have been shipped with an existing version of RedBoot, which can be upgraded to the current version using the instructions below.
The exec command as described in Chapter 2 is supported by RedBoot on this target, for executing Linux kernels. Only the command line and timeout options are relevant to this platform.
The memory map of this platform is fixed by the hardware (cannot be changed by software). The only attributes which can be modified are control over cacheability, as noted below.
Address Cache? Resource 00000000-03EFFFFF Yes SDRAM (via plugin DIMM) 03F00000-03FFFFFF No Unused (SDRAM) 10000000-1FFFFFFF No AX88796 Ethernet 20000000-2FFFFFFF No System FPGA 30000000-3FFFFFFF No MB93493 companion chip (unused) 40000000-FCFFFFFF ?? Unused FD000000-FDFFFFFF ?? FLASH (ROM3,ROM4) (unused) FE000000-FEFFFFFF No Miscellaneous on-chip I/O FF000000-FFFFFFFF No RedBoot FLASH (16MiB)
NOTE: The only configuration currently suppored requires a 64MiB SDRAM DIMM to be present on the CPU card. No other memory configuration is supported at this time.
These shell variables provide the platform-specific information needed for building RedBoot according to the procedure described in Chapter 3:
export TARGET=mb93093 export ARCH_DIR=frv export PLATFORM_DIR=mb93093
The RedBoot image occupies flash addresses 0xFF000000 - 0xFF03FFFF. To execute it copies itself out of there to RAM at 0x03E00000. RedBoot reserves memory from 0x00000000 to 0x0001FFFF for its own use. User programs can use memory from 0x00020000 to 0x03DFFFFF. RAM based RedBoot configurations are designed to run from RAM at 0x00020000.