| 摘要 |
A method and apparatus for processing the information in a sequence of bar code symbols. The information contained in one symbol can be decoded and processed while the information in the next symbol is being gathered. A pulse width counter, under control of a microprocessor, accumulates counts representing the widths of the elements of a bar code symbol and the accumulated counts are latched into a separate latch buffer which is then transferred into the microprocessor memory by a direct memory access controller. A program in the microprocessor operates on the information stored in the microprocessor memory to decode, process and output the data and/or commands contained within a given symbol as the pulse width counter is accumulating the counts that represent the next symbol to be read. If the input device is an automated scanner, the scanner's Start-of-Scan signal is used by the microprocessor to specify the beginning and end of each scan. If the input device is a wand, the microprocessor interprets an overflow of the pulse width counter as signifying the end of the wand scan.
|
