System and method for communication over a bus
Systems and methods for communicating data over a communication bus are disclosed. In some aspects, the data is digital information communicated over a multiple-line bus connecting two or more electronic devices such as integrated circuits. The disclosure presents useful formats for arranging data into data cells communicated over the bus, and include some exemplary features as shared clock signals, Ready bit information, and vertical parity checking.
1 . A method for exchanging digital data between devices over a bus, comprising:
providing at least one bit of data to indicate the type of digital data being exchanged;
providing at least one bit of data to indicate whether a device coupled to the bus is ready to communicate with other devices over the bus; and
providing at least one vertical parity bit for checking for error conditions in corresponding bits of the digital data.
2 . The method of claim 1 , further comprising logically grouping the digital data into a data cell.
3 . The method of claim 1 , further comprising including any flow control data within the data cell.
4 . The method of claim 1 , further comprising at least one byte of data for carrying an information payload across the bus.
5 . The method of claim 4 , further comprising at least one bit of data to indicate a number of bytes of data carrying an information payload.
6 . The method of claim 1 , wherein the at least one bit of data to indicate the type of digital data being exchanged comprises at least one combination of bits to indicate that the digital data is of a null type, carrying no payload therein.
7 . The method of claim 1 , further comprising clocking the devices using a common clock signal.
8 . A system for transferring digital data between at least two devices, comprising:
a communication bus having a plurality of communication lines, the communication bus coupled at a first end thereof to a first device and coupled at a second end thereof to a second device;
at least one of the plurality of communication lines providing at least one bit of data to indicate the type of digital data being exchanged;
at least one of the plurality of communication lines providing at least one bit of data to indicate whether any of the devices coupled to the communication bus are ready to communicate with other devices over the communication bus; and
the plurality of communication lines providing vertical parity bits for checking for error conditions in corresponding bits of the digital data.
9 . The system of claim 8 , further comprising a clock input line of a first device, said clock input line providing a clock signal that is shared with clock input lines on at least one other device.
10 . The system of claim 8 , further comprising at least one of the plurality of communication lines providing flow control data.
11 . The system of claim 8 , being further constructed as part of an integrated circuit for use in a communication computer system.
12 . The system of claim 11 , wherein the system receives communication data according to a communication standard format.
13 . A method for generating a digital data cell to be sent from a first device to a second device over a communication bus, the cell comprising:
a byte including a descriptor of the type of digital data cell;
a byte including at least one bit to indicate that the first device is ready to exchange digital data with the second device;
at least one byte to indicate a number of information payload bytes in the digital data cell;
at least one byte carrying information payload data; and
a byte of data including a plurality of vertical parity bits corresponding to the other bytes of data in the digital data cell.
14 . The method of claim 13 , wherein the byte including a descriptor of the type of digital data cell, and the byte including at least one bit to indicate that the first device is ready to exchange digital data with the second device, comprise a same byte that includes both the descriptor of the type of digital data cell and the at least one bit to indicate that the first device is ready.