Hi Marius, I am in the process of writing a driver for the W83L785TS-S. I would like you to answer a few question if possible: > Don't worry about the different partnumber in the link, they made a > mistake in the document name. You'll see the correct partnumber in the > document itself. Yes, noticed that. > There are other mistakes too: > Page 8 says "The 8-bit temperature data can be obtained by reading the > register." without telling you which one (it's CR27). Agreed. > In the tables on page 10,13 and 20 the values for R1 are wrong in the > row 85?C/30?C (should be 9.1K instead of 91K) and in the row 85?C/32?C > (should be 6.8K instead of 68K). Of course now that I understand the > purpose of those resistors I realize that they don't matter for a > device driver. That's right, we don't care, but thanks for the clarification anyway. > Most important is the mistake on page 10 where the sentence reads: > "When monitoring CPUT1 (Pin 2) temperature exceeds temperature fault > limit(ex: 90 o C) in CR26, or CR27, pin6 TEMP_FAULT# will be > asserted.". This should really read: "When monitoring CPUT1 (Pin 2) > temperature in CR27 exceeds the temperature fault limit in CR26 (ex: > 90?C) pin6 TEMP_FAULT# will be asserted.". > On page 13 the document declares CR26 to be reserved, but I checked on > my board and it does indeed contain the temperature fault limit value. I'm rather skeptical for this one. I would read the temperature fault limit from register 0x53, according to the data sheet. That said, the value in this register, from a dump one user provided, is 100, while I would expect 85 of 90. I think that the confusion with register 0x26 in Winbond's sheet comes from the fact that this register holds a second temperature value in the W83L785R, and the 785TS looks like a cut down version of the 785R. But I have value 89 in this register, so I admit it would be a reasonable value for a limit as well, although that's neither 85 nor 90 either. Could you provide a dump (using i2cdump) of your chip so that I would have a second set of data? For now my driver is read-only. I do not allow the user to write a custom limit. There are two reasons for that: 1* I'm still not sure which register it is. 2* I'm not even sure it is possible to change this value. The datasheet says the value is latched at startup, maybe that's not something we can/should change after. If you volunteer to make write tests, let me know and I'll tell you what to do exactly. > Another thing to note is that the 7-bit i?c address is 0101110. > Normally the lowest bit indicates reading from or writing to the chip. > This would make 0x5C the read and 0x5D the write address. However the > chip is clearly accessible at the address 0x2E on the A7N8X (same > 7-bit address just shifted to the right). I don't see any problem here. I2C addresses are almost always given as 7 bit values. This is the real address of the chips. The fact that you have to append a 0 or a 1 to write or read to/from the chip is another thing. I've seen people using the "read address" instead of the 7-bit address but that's confusing IMHO. So Winbond is right here :) We can't blame them all the time. -- Jean Delvare http://www.ensicaen.ismra.fr/~delvare/
