Communication between master unit and slave unit with efficient protocol

United States Patent [w]

S0rensen

US005952932A [ii] Patent Number: [45] Date of Patent:

5,952,932 Sep. 14,1999

[54] COMMUNICATION BETWEEN MASTER UNIT AND SLAVE UNIT WITH EFFICIENT PROTOCOL

[75] Inventor: Bent S0rensen, Billund, Denmark

[73] Assignee: Interlego AG, Baar, Switzerland

[21] Appl. No.: 08/987,154 [22] Filed: Dec. 8, 1997

[51] Int. CI. 11(14.1 3/24

[52] U.S. CI 340/825.07; 370/470; 370/471;

370/473; 370/522; 370/523; 370/527; 395/200.38; 395/200.6; 395/200.57; 395/200.67; 375/358

[58] Field of Search 340/825.07; 395/200.38,

395/200.6, 200.57, 200.67; 370/470, 471, 473, 522, 523, 527, 280; 375/358

[56] References Cited

U.S. PATENT DOCUMENTS

5,530,436 6/1996 Tabib et al 340/825.07

5,740,199 4/1998 Sibigtroth 370/280

A method ol communication between a master unit and a slave unit, including the steps ol: sending at least a command byte Irom the master unit to the slave unit including data byte counter bits to be interpreted by the slave unit according to the following rule set; il said data byte counter bits belong to a first set, then said data byte counter bits contain information representing a number ol associated data bytes, which is the expected number ol data bytes; il said data byte counter bits belong to a second set, then said data byte counter bits contain information representing a number which must be decoded before the expected number ol data bytes is obtained; receiving at least the command byte; interpreting the command byte; and receiving the number ol data bytes required by the rule set.

55 Claims, 5 Drawing Sheets