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1 | This directory contains board specific code for a generic MPC860T based |
2 | embedded computer, called 'GEN860T'. The design is generic in the sense that | |
3 | common, readily available components are used and that the architecture of the | |
7aa78614 | 4 | system is relatively straightforward: |
c609719b WD |
5 | |
6 | One eight bit wide boot (FLASH) memory | |
7 | 32 bit main memory using SDRAM | |
8 | DOC 2000+ | |
9 | Ethernet PHY | |
10 | Some I2C peripheral devices: Atmel AT24C256 EEPROM, Maxim DS1337 RTC. | |
11 | Some other miscellaneous peripherals | |
12 | ||
13 | NOTE: There are references to a XIlinx FPGA and Mil-Std 1553 databus in this | |
14 | port. I guess the computer is not as generic as I first said 8) However, | |
15 | these extras can be safely ignored. | |
16 | ||
17 | Given the GEN860T files, it should be pretty easy to reverse engineer the | |
18 | hardware configuration, if that's useful to you. Hopefully, this code will | |
19 | be useful to someone as a basis for a port to a new system or as a head start | |
20 | on a custom design. If you end up using any of this, I would appreciate | |
21 | hearing from you, especially if you discover bugs or find ways to improve the | |
22 | quality of this U-Boot port. | |
23 | ||
24 | Here are the salient features of the system: | |
7aa78614 WD |
25 | Clock : 33.3 Mhz oscillator |
26 | Processor core frequency : 66.6 Mhz if in 1:2:1 mode; can also run 1:1 | |
27 | Bus frequency : 33.3 Mhz | |
c609719b WD |
28 | |
29 | Main memory: | |
30 | Type : SDRAM | |
31 | Width : 32 bits | |
7aa78614 | 32 | Size : 64 mibibytes |
c609719b WD |
33 | Chip : Two Micron MT48LC16M16A2TG-7E |
34 | CS : MPC860T CS1*/UPMA | |
35 | UPMA CONNECTIONS: | |
36 | SDRAM A10 : GPLA0* | |
37 | SDRAM CAS* : GPLA2* | |
38 | SDRAM WE* : GPLA3* | |
39 | SDRAM RAS* : GPLA4* | |
40 | ||
41 | Boot memory: | |
42 | Type : FLASH | |
43 | Width : 8 bits | |
7aa78614 | 44 | Size : 16 mibibytes |
c609719b WD |
45 | Chip : One Intel 28F128J3A (StrataFlash) |
46 | CS : MPC860T CS0*/GPCM (this is the "boot" chip select) | |
47 | ||
48 | EEPROM memory: | |
49 | Type : Serial I2C EEPROM | |
50 | Width : 8 bits | |
51 | Size : 32 kibibytes | |
52 | Chip : One Atmel AT25C256 | |
53 | CS : 0x50 (external I2C address pins on device are tied to GND) | |
54 | ||
55 | Filesystem memory: | |
56 | Type : NAND FLASH (Toshiba) | |
57 | Width : 8 bits (i.e. interface to DOC is 8 bits) | |
7aa78614 | 58 | Size : 32 mibibytes |
c609719b WD |
59 | Chip : One DiskOnCHip Millenium Plus (DOC 2000+) |
60 | CS : MPC860T CS2*/GPCM | |
61 | ||
62 | Network support: | |
63 | MAC : MPC86OT FEC (Fast Ethernet Controller) | |
64 | PHY : Intel LXT971A | |
65 | MII Addr: 0x0 (hardwired on the board) | |
66 | MII IRQ : | |
67 | ||
68 | Console: | |
69 | RS-232 on SMC1 (Maxim MAX3232 LVCMOS-RS232 level shifter) | |
70 | ||
71 | Real Time Clock: | |
72 | Type : Low power, I2C interface | |
73 | Chip : Maxim DS1337 | |
74 | CS : Address 0x68 on I2C bus | |
75 | ||
76 | The MPC860T's internal RTC has a defect in Mask rev D that increases | |
77 | the current drain on the KAPWR line to 10 mA. Since this is an | |
78 | unreasonable amount of current draw for a RTC, and Motorola does not | |
79 | plan to fix this in future mask revisions, a serial (I2C) RTC that | |
80 | works has been included instead. NOTE that the DS1337 can be | |
81 | configured to output a 32768 Hz clock while the main power is on. | |
82 | This clock output has been routed to the MPC860T's EXTAL pin to allow | |
83 | the internal RTC to be used. NOTE also that due to yet another | |
84 | defect in the rev D mask, the RTC does not operate reliably when the | |
85 | internal RTC divisor is set to use a 32768 Hz reference. So just use | |
86 | the I2C RTC. | |
87 | ||
88 | Miscellaneous: | |
89 | Xilinx Virtex FPGA on CS3*/GPCM. | |
90 | Virtex FPGA slave SelectMap interface on cs4*/UPMB. | |
91 | Mil-Std 1553 databus interface on CS5*/GPCM. | |
92 | Audio sounder (beeper) with digital volume control connected to SPKROUT. | |
93 | ||
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94 | SC variant: |
95 | A reduced-feature version of the GEN860T port is also supported: GEN860T_SC. | |
96 | The 'SC' variant only provides support for the Virtex FPGA, SDRAM main | |
97 | memory, EEPROM and flash memory. The system clock frequency is reduced | |
98 | to 24 MHz. | |
99 | ||
c609719b WD |
100 | Issues: |
101 | The DOC 2000+ returns 0x40 as its device ID when probed using the method | |
102 | desxribed in the DOC datasheet. Unfortunately, the U-Boot DOC driver | |
103 | does not recognize this device. As of this writing, it seems that MTD | |
104 | does not support the DOC 2000+ either. | |
105 | ||
106 | Status: | |
107 | Everything appears to work except DOC support. As of this writing, | |
108 | David Woodhouse has stated on the MTD mailing list that he has no | |
109 | knowledge of the DOC Millineum Plus and therfore there is no support | |
110 | in MTD for this device. I wish I had known this sooner :( | |
111 | ||
112 | The GEN860T board specific files and configuration is based on the work | |
7aa78614 | 113 | of others who have contributed to U-Boot. The copyright and license notices |
c609719b WD |
114 | of these authors have been retained wherever their code has been reused. |
115 | All new code to support the GEN860T board is: | |
116 | ||
7aa78614 | 117 | (C) Copyright 2001-2003 |
c609719b WD |
118 | Keith Outwater (keith_outwater@mvis.com) |
119 | ||
120 | and the following license applies: | |
121 | ||
122 | This program is free software; you can redistribute it and/or | |
123 | modify it under the terms of the GNU General Public License as | |
124 | published by the Free Software Foundation; either version 2 of | |
125 | the License, or (at your option) any later version. | |
126 | ||
127 | This program is distributed in the hope that it will be useful, | |
128 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
129 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
130 | GNU General Public License for more details. | |
131 | ||
132 | You should have received a copy of the GNU General Public License | |
133 | along with this program; if not, write to the Free Software | |
134 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, | |
135 | MA 02111-1307 USA | |
136 | ||
137 | Thanks to Wolfgang Denk for a great software package and to everyone | |
138 | who contributed to its development. | |
139 | ||
140 | Keith Outwater | |
141 | Sr. Staff Engineer | |
142 | Microvision, Inc. | |
143 | <keith_outwater@mvis.com> | |
144 | <outwater@eskimo.com> |