| 摘要 |
<p>A franking machine includes an electronic microprocessor (10) having pairs of ports (11, 12; 13, 14; 15, 16) for communication between the microprocessor and other electronic devices (17, 18, 25, 28) comprising memories (17, 18), a keyboard display device (25) or a real time clock device (28). One port of each pair is utilised for clock signals and the other port of each pair is utilised for control, address and data signals. The memory devices are normally in an inactive mode and reading or writing of data is initiated by a signal format output by the microprocessor which specifies a device address and a memory location within the device. The communication between the microprocessor and the electronic devices includes the returning of acknowledgement signals from the devices to the microprocessor. In an initialisation routine, the receipt of an acknowledgement signal or absence thereof may be utilised to enable the microprocessor to identify which one of a number of versions of a device is installed and to select an appropriate software routine.</p> |
