Hallo Zusammen, Ich habe ein Problem mit dem Baustein DS2480 (http://pdf1.alldatasheet.com/datasheet-pdf/view/58621/DALLAS/DS2480.html). Und zwar möchte ich die Hexzahl 0xE3 (227) in den Speicher meines 1-Wire EEPROMs schreiben. Dies ist allerdings der Ausdruck, dass das schreiben beendet ist. Gibt es da irgendeine Möglichkeit diese Zahl trotzdem zu schreiben? Muss doch irgendwie möglich sein... Gruss Dexter
Hallo, Der wichtige Abschnitt des Datenblatts ist dieser hier: "While being in the Data Mode the DS2480 checks each byte received from the host for the reserved code that is used to switch back to Command Mode. To be able to write any possible code (including the reserved one) to the 1–Wire bus, the transition to the Command Mode is as follows: After having received the code for switching to Command Mode, the device temporarily enters the Check Mode where it waits for the next byte. If both bytes are the same, the byte is sent once to the 1–Wire bus and the device returns to the Data Mode. If the second byte is different from the reserved code, it will be executed as command and the device finally enters the Command Mode. As a consequence, if the reserved code that normally switches to Command Mode is to be written to the 1–Wire bus, this code byte must be sent twice (duplicated). This detail must be considered carefully when developing software drivers for the DS2480." D.h. um 0xE3 in den Speicher zu Schreiben musst du das Byte zweimal senden. Dadurch erkennt der DS2480 dass es sich nicht um einen Befehl sondern um Daten handelt. Viele Grüsse, Michael
Steht doch im Datenblatt: "To be able to write any possible code (including the reserved one) to the 1-Wire bus, the transition to the Command Mode is as follows: After having received the code for switching to Command Mode, the device temporarily enters the Check Mode where it waits for the next byte. If both bytes are the same, the byte is sent once to the 1-Wire bus and the device returns to the Data Mode. If the second byte is different from the reserved code, it will be executed as command and the device finally enters the Command Mode. As a consequence, if the reserved code that normally switches to Command Mode is to be written to the 1-Wire bus, this code byte must be sent twice (duplicated)." Peter
Vielen Dank für die schnelle Antwort. Diese Stelle hab ich nicht gesehen im Datenblatt... Wohl überlesen. Gruss Dexter