How to read Dallas iButton DS1992
John Bond
Posts: 369
Hi Guys
·
I’m using a bunch of Dallas iButton DS1992 fobs to store information. They are 1Wire Access control devices and can store 128K byte in 4 pages of 32 bytes each. The information is first stored in the Scratchpad and you then transfer it to the ROM page. I store different information on each of the pages, for example, the persons name on page0, their access level on page1, the department they are in on page2. This bit of code seems to work.
·
When I extract the Page Read code from the main program to produce a stand alone iButton reader, the debug window displays 4 identical pages of the last ROM page I wrote.
·
I’m using a BS2p and I’ve spent several days trying to solve this.
·
Does anyone have experience with these devices?
·
Kind regards from Kwa Dukuza
John Bond
·
I’m using a bunch of Dallas iButton DS1992 fobs to store information. They are 1Wire Access control devices and can store 128K byte in 4 pages of 32 bytes each. The information is first stored in the Scratchpad and you then transfer it to the ROM page. I store different information on each of the pages, for example, the persons name on page0, their access level on page1, the department they are in on page2. This bit of code seems to work.
·
When I extract the Page Read code from the main program to produce a stand alone iButton reader, the debug window displays 4 identical pages of the last ROM page I wrote.
·
I’m using a BS2p and I’ve spent several days trying to solve this.
·
Does anyone have experience with these devices?
·
Kind regards from Kwa Dukuza
John Bond
Comments
If I always set the page to 00h and move the Read Offset between 00h and 60h, it reads everyting and doesn't see the page boundries. It works perfectly and is also a much easier way to handle the data because fields can overlap pages.
Wow, that was a marathon fault finding excercise. I sometime wonder why electronics companies make protocols so complex. It's also nice to be writing myself some advice on this forum. After all, I've got a lot of good advice here in the past.
Kind Regards from Kwa Dukusa
John Bond