MIPS/VR4375 NEC DDB-VRC4375

Overview

RedBoot supports only serial port 1, which is connected to the upper of the stacked serial connectors on the board. The default serial port settings are 38400,8,N,1. FLASH management is also supported.

The following RedBoot configurations are supported:

Configuration	Mode	Description	File
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

Initial Installation Method

A device programmer should be used to program a socketed FLASH part (AMD 29F040). The board as delivered is configured for a 512K EPROM. To install a FLASH ROM, Jumpers J30, J31 and J36 need to be changed as described in the board's User Manual.

Special RedBoot Commands

None.

Memory Maps

RedBoot sets up the memory map primarily as described in the board's User Manual. There are some minor differences, noted in the following table:

Physical                Virtual                 Resource
Addresses               Addresses
00000000-01FFFFFF       80000000-81FFFFFF       Base SDRAM (cached)
00000000-01FFFFFF       A0000000-A1FFFFFF       Base SDRAM (uncached)
0C000000-0C0BFFFF       AC000000-AC0B0000       PCI IO space
0F000000-0F0001FF       AF000000-AF0001FF       VRC4375 Registers
1C000000-1C0FFFFF       BC000000-BC0FFFFF       VRC4372 Registers
1C100000-1DFFFFFF       BC100000-BDFFFFFF       PCI Memory space
1FC00000-1FC7FFFF       BFC00000-BFC7FFFF       FLASH ROM
80000000-8000000D       C0000000-C000000D       RTC
8000000E-80007FFF       C000000E-C0007FFF       NVRAM
81000000-81FFFFFF       C1000000-C1FFFFFF       Z85C30 DUART
82000000-82FFFFFF       C2000000-C2FFFFFF       Z8536 Timer
83000000-83FFFFFF       C3000000-C3FFFFFF       8255 Parallel port
87000000-87FFFFFF       C7000000-C7FFFFFF       Seven segment display

NOTE: By default the VRC4375 SIMM control registers are not programmed since the values used must depend on the SIMMs installed. If SIMMs are to be used, correct values must be placed in these registers before accessing the SIMM address range.

NOTE: The allocation of address ranges to devices in the PCI IO and memory spaces is handled by the eCos PCI support library. They do not correspond to those described in the board User Manual.

NOTE: The MMU has been set up to relocate the VRC4372 supported devices mapped at physical addresses 0x8xxxxxxx to virtual addresses 0xCxxxxxxx.

Ethernet Driver

The ethernet driver is in two parts:

A generic ether driver for the Intel i21143 device is located in devs/eth/intel/i21143. Its package name is CYGPKG_DEVS_ETH_INTEL_I21143.

The platform-specific ether driver is devs/eth/mips/vrc4375. Its package is CYGPKG_DEVS_ETH_MIPS_VRC4375. This tells the generic driver the address in IO memory of the chip, for example, and other configuration details. The ESA (MAC address) is by default collected from on-board serial EEPROM, unless configured statically within this package.

Rebuilding RedBoot

These shell variables provide the platform-specific information needed for building RedBoot according to the procedure described in Chapter 3:

export TARGET=vrc4373
export ARCH_DIR=mips
export PLATFORM_DIR=vrc4373

The names of configuration files are listed above with the description of the associated modes.