Hi all, I asked for help a while ago about the I2C problem for IRIS + MTS310 board when adjusting the magnetometer gain with the AD5242 component : http://www.mail-archive.com/[email protected]/msg22159.html
I fixed it a month ago but didn't find the time since then to post on the mailing. So first of all, I found this post which helped me a little : http://mail.millennium.berkeley.edu/pipermail/tinyos-help/2007-January/021749.html But instead of changing the code directly in "HplAtm128I2CBusP.nc", I prefer changing the argument of the init call in "Atm128I2CMasterPacketP.nc" in the function "AsyncStdControl.start()" : I changed >> call I2C.init(FALSE) to >> call I2C.init(TRUE) After this, the I2C bus was truly enabled, so I thought the problem was fixed, but I was wrong : the gainAdjustX or Y function had no effect at all. So I decided to build a logic analyzer like this one : http://www.xs4all.nl/~jwasys/old/diy2.html It work wonderfully. I started by sending known characters on the bus, like 0xAA55 : http://img297.imageshack.us/img297/1624/0xaa55writeenvt2.jpg I looked at the AD5242 datasheet and I recognized the adress of the compoment in the first byte, but it was shifted left of 1 bit (the grey rectangles shows that). So the adress is obviously wrong, and that explains why the component never acknowledge ("A" bit should be 0 if the component had acknowledge). The reason : this line in "Atm128I2CMasterPacketP.nc" (again !) : >> call I2C.write(((packetAddr & 0x7f) << 1) | ATM128_I2C_SLA_WRITE); I replaced it by >> call I2C.write( packetAddr | ATM128_I2C_SLA_WRITE ); And I retried with 0x00AA ... and it's working now ! : http://img398.imageshack.us/img398/4330/0x00aawriteokenqz1.jpg Every "A" bit was acknowledged... So I tried some gain values with gainAdjustY() and the magnetometer signal was finally visible. Once again I thought it was OK, but there was one more problem, I couldn't get the X axis working, with gainAdjustX(). This last problem was about the subadress of the AD5242, in "MagP.nc", in the function "Mag.gainAdjustX(uint8_t val)" : Instead of >> gainData[0] = 0x01; you must put >> gainData[0] = 0x80; the subadress bit is the MSB, referring to the datasheet... And then, I had my two-axis magnetometer working perfectly. I developped a simple dichotomy algorithm to center the signals, and it's working very well, taking only 5 steps to center them. Voilà ! I don't know if some TinyOS developpers agrees with what I did, but if they do, maybe they can change the sources. Anyway, I hope it will help for other people in the same situation. Thanks again Miklos for trying to help me with my previous posts. Raphael Polonowski PS : sorry for my poor english _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
