1 File: COBRAXXXX-FAQ_en.txt
2 Location: uClinux-dist/Documentation/COBRAXXXX/en/
3 and COBRAXXXX-CD/documentation/boards/
4 Author: Heiko Degenhardt (linux@sentec-elektronik.de)
5 Contents: Frequently asked questions about the board.
7 Date: Wed Mar 24 17:59:40 CET 2004
8 License: This document is under the GNU GPL
9 (see uClinux-dist/COPYING)
10 ______________________________________________________________________
14 040324 v01.00 Creation
15 (new file, because it is for both boards now)
17 ______________________________________________________________________
21 Q: What does "COBRA5272" or "COBRA5282" mean?
22 A: COBRA stands for "COldfire Board for Rapid Applications". The 5272
23 shows that the board is based on Motorola's ColdFire 5272. The
24 COBRA5282 is based on the MCF5282.
26 Q: Where can I order the boards? Is there a web site?
27 A: You can order the boards via the German distributor ELEKTRONIKLADEN.
28 Their web sites for the boards are
29 http://www.elektronikladen.de/cobra5272.html and
30 http://www.elektronikladen.de/cobra5282.html.
31 The home page of the boards is at
32 http://www.sentec-elektronik.de/cobra/.
34 Q: Ok, now I have the board. What are the first steps I should do
35 to get a running image?
36 A: Now that you have downloaded the uClinux-dist sources please read
37 ./Documentation/COBRAXXXX/en/COBRAXXXX-Getting-started_en.txt
38 to get started. If you obtained the COBRAXXXX-CD, you will find
39 all related pdf files in /documentation/boards/.
43 Q: What cable have I to use for communicating via the serial port?
44 A: You can use a "normal" serial cable, not a so called "null modem
47 Q: What are the standard values for the communication parameters?
48 A: Serial Port: 19200 Baud, 8n1
49 Server IP: 192.168.100.1
50 Client IP: 192.168.100.2
51 Netmask: 255.255.255.0
53 Ethernet: 00:00:00:00:00:01
54 (The default MAC address for the COBRA5282 is 00:CF:52:82:CF:01).
56 Q: How can I configure the parameters for the commands that are
57 executed on kernel start up?
58 A: At start-up of the uClinux kernel the commands of the file
59 uClinux-dist/vendors/senTec/romfs/etc/rc get executed.
60 Here you can configure for instance the IP address, the netmask,
61 if you want to mount a directory via NFS, and if so, which
62 directory gets mounted and so on.
63 (HINT: To get a detailed description you should look into the
64 manual pages of the commands, eg. "man ifconfig").
68 Q: The board always does a reset. What can I do?
69 A: Here are some things to check:
70 a) Increase the value of the current clamp:
71 The power supply should give around 500mA at 6V (if you have a
72 starter kit with a linear voltage regulator you can try to
73 increase the voltage to around 7.5V).
75 b) Measure the voltage:
76 On the starterkit board you find opposite to the bdm connector
77 a row of LED's (D3..D10). On the left site of it there is a
78 edge connector. There you have plus on the one site, and ground
79 on the other. The voltage there should be >3.15V.
80 On the COBRA5282 board, near the breadbord area, you find
81 2 rows with 4 pins each. They are labeled "GND" and "+3.3V".
82 Between 2 of their pins you should measure a voltage >3.15V.
84 Q: "make" gives an error about a missing reference to
86 A: You must set CONFIG_MTD_PARTITIONS in the kernel config!
88 Q: I don't have a BDM-Adaptper. Where can I get one?
89 A: You can look for it for instance at http://www.pemicro.com or
90 http://www.cybertec.com.au. Make sure to use a
91 "Shielded ColdFire BDM Adapter, 3.3V".
93 Q: After "make dep" or "make" there are many messages scrolling out
94 of the terminal window. How is it possible to read them?
95 A: You can for instance "pipe" them into the program "tee" that
96 writes them into a file, eg. "errs". To do that, just type:
97 "make 2>&1 | tee errs".
99 Q: The tftp download from dBUG doesn't work, gives errors or
100 simply stops, but my cabling is correct. What can I do?
101 A: There seem to be errors in the dBUG source code that make
102 it less tolerant against errors concerning problems with
103 the network interfaces. As far as we can tell the download
104 works more stable if you give the file name on the command
105 line, e.g. "dn image.bin".
106 You should set the network speed to 10MBit on the COBRA5272
107 and to 100MBit half duplex on the COBRA5282. To do that
108 you can for instance use mii-tool on a Linux host.
109 There seem to be no problems if you use a switch or hub
110 to connect the board with your PC.
113 Q: I want to use the external bus for my own periphals. With the
114 oscilloscope I can see, that the external chipselects are
115 "floating", and so my periphals cannot work. What can I do?
116 A: The buffers IC 0201 - IC 0209 (see Schematic p. 3) are selected
117 with the same chipselects. When the buffers are disabled, the
118 level of all external signal (includig the chipselects) are
119 falling to Ground. To avoid this, the used chipselects can
120 be pulled up (eg. with 4,7k) to 3,3V.
125 If you find errors, or have some tips or questions concerning this
126 FAQ, please send an email to linux@sentec-elektronik.de. You'll
127 easily find out that I'm not a native English speaker, so feedback
130 ______________________________________________________________________
131 (c) 2004, senTec Elektronik Gmbh, Heiko Degenhardt