Adapter with FIFO and buffers for interfacing a handheld scanner to the parallel printer port of a portable computer

An adapter system for interfacing a handheld scanner to a portable computer lacking a bidirectional parallel data port, the portable computer having a parallel printer port that includes a unidirectional data bus and a printer control and status bus, the adapter system comprising:

• (a) a data buffer for receiving serial video data and scanner controller signals from the handheld scanner and converting the serial video data into parallel video data;
• (b) a scanner resolution latch coupled to said data buffer, said scanner resolution latch receiving scanner controller signals from the data buffer, latching scanning resolution data from the scanner controller signals, and providing the scanning resolution data to the printer control and status bus of the parallel printer port;
• (c) a memory unit coupled to said data buffer, said memory unit receiving and storing the parallel video data from the data buffer;
• (d) a data latch buffer coupled to said memory unit, said data latch buffer receiving the parallel video data from the memory unit and providing the parallel video data to the printer control and status bus of the parallel printer port;
• and
• (e) a memory controller coupled between the data buffer and the memory unit, said memory controller receiving the scanner controller signals from the data buffer and generating write signals to the memory unit so as to enable the memory unit to store the parallel video data therein, said memory controller further coupled to the printer control and status bus of the parallel printer port and generating an interrupt signal and providing the interrupt signal to the printer control and status bus so as to inform the computer that video data is available when a predetermined quantity of the parallel video data has been stored in the memory unit.

An adapter for transmitting serial data from a handheld scanner to a host computer lacking a bidirectional parallel data port, the host computer having a parallel printer port that includes unidirectional data lines and printer control and status lines, wherein the serial data is transferred in parallel through the printer control and status lines of the parallel printer port, the adapter comprising:

• (a) a data buffer, coupled to the handheld scanner, for receiving serial data and timing signals indicative of the availability of serial data from the handheld scanner and for converting the serial data into parallel data;
• (b) a scanner resolution latch coupled to the data buffer, said scanner resolution latch receiving scanner control signals from the data buffer, latching scanning resolution data from the scanner control signals, and providing the scarming resolution data to the printer control and status lines of the parallel printer port;
• (c) a memory unit, coupled between the data buffer and the printer control and status lines of the parallel printer port, for receiving and storing the parallel data from the data buffer;
• (d) a data latch coupled between the memory unit and the printer control and status lines of the parallel printer port, said data latch receiving parallel data from the memory unit and providing the parallel data to the printer control and status lines;
• (e) a memory controller coupled to the data buffer and the memory unit, said memory controller receiving the timing signals from the data buffer and generating write signals to the memory unit to direct the memory unit to store parallel data, said memory controller further coupled to one of the printer control and status lines on the parallel port of the host computer, wherein the memory controller generates an interrupt signal on said one of the printer control and status lines when a predetermined quantity of parallel data has been stored in the memory unit to inform the host computer that parallel data is available, wherein upon receiving the interrupt signal the host computer generates a timing pulse to transfer the parallel data from the memory unit over the printer control and status lines to the host computer.