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diff --git a/roms/u-boot/board/gen860t/README b/roms/u-boot/board/gen860t/README new file mode 100644 index 00000000..3ef8ae19 --- /dev/null +++ b/roms/u-boot/board/gen860t/README @@ -0,0 +1,131 @@ +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> |