Method and system for expanding the i/o on i/o limited devices

A method for I/O data transfer comprising:

• initializing a stored value of a first input bank;
• sampling a first value of said first input bank;
• detecting a change in said input bank;
• storing a state of a data bit of said input bank in a FIFO;
• storing a bank identifier in said FIFO;
• sampling an I/O line via a first READ cycle;
• driving said I/O line with a next data entry from said FIFO;
• sampling substantially all digital inputs;
• storing any detected changes in said FIFO;
• transmitting all values in said FIFO to a Digital Device during a second READ cycle;
• transmitting to said Digital Device a last value read;
• changing a digital output when a WRITE occurs and said Digital Device explicitly selects said digital output to be set;
• writing an entire bank in response to a bit change;
• decoding said digital output;
• and
• latching said digital output until said digital output is overwritten via a third WRITE command to said input bank from said Digital Device.

An I/O system comprising:

• a memory including a first input bank, said memory adapted to reset and thereby clear a stored first value within said first input bank;
• a change detector adapted to sample a second value within said first input bank, said change detector further adapted to detect a first change and generate a first store signal in response thereto, said change detector further adapted to sample substantially all Digital I/O Device inputs in response to completion of necessary READ cycles and generate therefrom a second sample signal, said change detector further adapted to detect a second change and generate a second store signal in response thereto;
• a FIFO adapted to receive said first store signal and store a first state of input bank data bit and a first bank identifier in response thereto and generate therefrom a first bank signal, said FIFO further adapted to receive said second store signal and store a second state of input bank data bit and a second bank identifier in response thereto and generate therefrom a second bank signal, a Digital Device adapted to sample at least one Digital Device I/O line via a READ cycle and thereby generate an I/O sample signal, said Digital Device adapted to receive all values stored in said FIFO during said READ cycle, said Digital Device further adapted to receive a last value READ from said FIFO following reception of said all values;
• an I/O Transmit and Receive Control adapted to receive said I/O sample signal and drive said Digital Device I/O line to said Digital Device with a next data entry from said FIFO in response thereto;
• a decoder adapted to decode said output value signal;
• and
• a latch adapted to latch said output value signal until it is overwritten via a third write command to said entire bank from said Digital Device.