Data transfer method and apparatus having dual frequency operation

A method of transferring data to and from a master device and at least a first peripheral device utilizing a data bus, each master and peripheral device contains a corresponding controller, the method of transferring data comprising the steps of:

• initializing during a first initialization period, said step of initializing comprising the steps of:
• operating the data bus at a first data transfer rate, and
• assigning the at least first peripheral devices with an unique address wherein said step of assigning a unique address in the at least first peripheral further comprises the steps of:
• setting an address counter to a first counter value,
• transmitting said a first unique serial number on the data bus,
• reading a first value of the data bus,
• comparing said first value of the data bus to said first unique serial number,
• determining if the peripheral device is contending for use of the data bus, and
• assigning the address of said address counter to the peripheral device in absence of said contending for use of the data bus;
• detecting the end of said initialization period;
• and
• operating the data bus at a second data transfer rate responsive to said step of detecting.

A data transfer system for transferring data to and from a master device and at least a first peripheral device, the data transfer system including a data bus and at least a first peripheral controller and a first master controller, the data transfer system comprising:

• means for initializing the data transfer system during a first initialization period, said means for initializing comprising:
• means for operating the data bus at a first data transfer rate, and
• means for assigning the at least first peripheral device with an unique address comprises executing the steps of:
• setting an address counter to a first counter value,
• transmitting a first unique serial number on the data bus,
• reading a first value of the data bus,
• comparing said first value of the data bus to said first unique serial number,
• determining if the peripheral device is contending for use of the data bus, and
• assigning the address of said address counter to the peripheral device in absence of said contending for use of the data bus;
• means for detecting the end of said initialization period;
• and
• means, responsive to said means for detecting, for operating the data bus at a second data transfer rate.

A method of transferring data to and from a master device and at least a first peripheral device utilizing a data bus, each master and peripheral device contains a corresponding controller, the method of transferring data comprising the steps of:

• initializing during a first initialization period, said step of initializing comprising the steps of:
• operating the data bus at a first data transfer rate, and
• assigning the at least first peripheral device with an unique address comprising the steps off
• setting an address counter to a first counter value,
• transmitting said a first unique serial number on the data bus,
• reading a first value of the data bus,
• comparing said first value of the data bus to said first unique serial number,
• determining if the peripheral device is contending for use of the data bus, and
• assigning the address of said address counter to the peripheral device in absence of said contending for use of the data bus;
• detecting the end of said initialization period;
• and
• operating the data bus at a second data transfer rate responsive to said step of detecting.