--- /dev/null
+This directory contains board specific code for a generic MPC860T based
+embedded computer, called 'GEN860T'. The design is generic in the sense that
+common, readily available components are used and that the architecture of the
+system is relatively straightforward:
+
+ One eight bit wide boot (FLASH) memory
+ 32 bit main memory using SDRAM
+ DOC 2000+
+ Ethernet PHY
+ Some I2C peripheral devices: Atmel AT24C256 EEPROM, Maxim DS1337 RTC.
+ Some other miscellaneous peripherals
+
+NOTE: There are references to a XIlinx FPGA and Mil-Std 1553 databus in this
+port. I guess the computer is not as generic as I first said 8) However,
+these extras can be safely ignored.
+
+Given the GEN860T files, it should be pretty easy to reverse engineer the
+hardware configuration, if that's useful to you. Hopefully, this code will
+be useful to someone as a basis for a port to a new system or as a head start
+on a custom design. If you end up using any of this, I would appreciate
+hearing from you, especially if you discover bugs or find ways to improve the
+quality of this U-Boot port.
+
+Here are the salient features of the system:
+Clock : 33.3 Mhz oscillator
+Processor core frequency : 66.6 Mhz if in 1:2:1 mode; can also run 1:1
+Bus frequency : 33.3 Mhz
+
+Main memory:
+ Type : SDRAM
+ Width : 32 bits
+ Size : 64 mibibytes
+ Chip : Two Micron MT48LC16M16A2TG-7E
+ CS : MPC860T CS1*/UPMA
+ UPMA CONNECTIONS:
+ SDRAM A10 : GPLA0*
+ SDRAM CAS* : GPLA2*
+ SDRAM WE* : GPLA3*
+ SDRAM RAS* : GPLA4*
+
+Boot memory:
+ Type : FLASH
+ Width : 8 bits
+ Size : 16 mibibytes
+ Chip : One Intel 28F128J3A (StrataFlash)
+ CS : MPC860T CS0*/GPCM (this is the "boot" chip select)
+
+EEPROM memory:
+ Type : Serial I2C EEPROM
+ Width : 8 bits
+ Size : 32 kibibytes
+ Chip : One Atmel AT25C256
+ CS : 0x50 (external I2C address pins on device are tied to GND)
+
+Filesystem memory:
+ Type : NAND FLASH (Toshiba)
+ Width : 8 bits (i.e. interface to DOC is 8 bits)
+ Size : 32 mibibytes
+ Chip : One DiskOnCHip Millenium Plus (DOC 2000+)
+ CS : MPC860T CS2*/GPCM
+
+Network support:
+ MAC : MPC86OT FEC (Fast Ethernet Controller)
+ PHY : Intel LXT971A
+ MII Addr: 0x0 (hardwired on the board)
+ MII IRQ :
+
+Console:
+ RS-232 on SMC1 (Maxim MAX3232 LVCMOS-RS232 level shifter)
+
+Real Time Clock:
+ Type : Low power, I2C interface
+ Chip : Maxim DS1337
+ CS : Address 0x68 on I2C bus
+
+ The MPC860T's internal RTC has a defect in Mask rev D that increases
+ the current drain on the KAPWR line to 10 mA. Since this is an
+ unreasonable amount of current draw for a RTC, and Motorola does not
+ plan to fix this in future mask revisions, a serial (I2C) RTC that
+ works has been included instead. NOTE that the DS1337 can be
+ configured to output a 32768 Hz clock while the main power is on.
+ This clock output has been routed to the MPC860T's EXTAL pin to allow
+ the internal RTC to be used. NOTE also that due to yet another
+ defect in the rev D mask, the RTC does not operate reliably when the
+ internal RTC divisor is set to use a 32768 Hz reference. So just use
+ the I2C RTC.
+
+Miscellaneous:
+ Xilinx Virtex FPGA on CS3*/GPCM.
+ Virtex FPGA slave SelectMap interface on cs4*/UPMB.
+ Mil-Std 1553 databus interface on CS5*/GPCM.
+ Audio sounder (beeper) with digital volume control connected to SPKROUT.
+
+SC variant:
+ A reduced-feature version of the GEN860T port is also supported: GEN860T_SC.
+ The 'SC' variant only provides support for the Virtex FPGA, SDRAM main
+ memory, EEPROM and flash memory. The system clock frequency is reduced
+ to 24 MHz.
+
+Issues:
+ The DOC 2000+ returns 0x40 as its device ID when probed using the method
+ desxribed in the DOC datasheet. Unfortunately, the U-Boot DOC driver
+ does not recognize this device. As of this writing, it seems that MTD
+ does not support the DOC 2000+ either.
+
+Status:
+ Everything appears to work except DOC support. As of this writing,
+ David Woodhouse has stated on the MTD mailing list that he has no
+ knowledge of the DOC Millineum Plus and therfore there is no support
+ in MTD for this device. I wish I had known this sooner :(
+
+The GEN860T board specific files and configuration is based on the work
+of others who have contributed to U-Boot. The copyright and license notices
+of these authors have been retained wherever their code has been reused.
+All new code to support the GEN860T board is:
+
+ (C) Copyright 2001-2003
+ Keith Outwater (keith_outwater@mvis.com)
+
+and the following license applies:
+
+SPDX-License-Identifier: GPL-2.0+
+
+Thanks to Wolfgang Denk for a great software package and to everyone
+who contributed to its development.
+
+Keith Outwater
+Sr. Staff Engineer
+Microvision, Inc.
+<keith_outwater@mvis.com>
+<outwater@eskimo.com>
Code Review / kvmfornfv.git / blobdiff