To design a peripheral which can send data from PC Parallel Port to Printer in wireless, hence required by two systems where first system connected to PC Parallel Port and second system connected with Printer. Communications wireless usually always is done by using serial transmission of asynchronous that is a serial transmission started with start bit and bit stop. Hence from that, system that is connect at Parallel Port PC must be can change parallel data from Parallel Port PC becomes serial of asynchronous and system that is connect at Printer changes serial data of asynchronous becomes parallel as required by printer.
In the application of this required retrieval of data in parallel from PC to system which you are create. After data taken able to be entered planning system, hence at process hereinafter (for wireless printer) the data can be continued serially for transmission in wireless. To do is interfacial between PC Parallel Port with system outside PC, beforehand must be known function of pins from Parallel Port and process happened when delivery of data takes place.
Process happened at delivery of data with Mode SPP is as follows:
· PC verifies condition of pin Busy and PE. If Pin Busy condition of low, hence printer doesn't stir. While if, when condition of PE high, hence medium paper not ready. For condition of medium business and also paper not ready (Errors Cartridge) hence PC must be awaiting is finite condition of business to end or paper has made ready.
· After condition of business ends and paper has made ready, hence data will be sent to finite D0 of D7 by terminated [by] a signal STB (active of low) what indicates data has made ready in finite D0 of D7. Printer can take data which has made ready the.
· Signal acknowledge given by printer to PC to ensure that printer has ready for receiving further data.
After condition of pin and job process is known, hence by using DST-51, a system bases on AT89C51, this process can be done by connecting the I/O-I/O like at picture 3 where bus data from Parallel Port connect to Port 1.
For the application of this data received from Parallel Port will be sent to serial of port by using communications UART is having speed transmission 600 bps. Safe speed applied for transmission infrared in distance that is far enough where signal infrared is modulation with frequency carrier 40 KHZ. At picture 4 seen two flowchart where first flowchart is flowchart at main program and second flowchart is flowchart from serial of interrupt. In the early of flowchart main program processed happened at the way program is started with initial hardware where at the process is done by serial initial of port as 600 bps, activates serial interrupt to receive feedback from part of system that is connect to printer.
Feedback in the form of serial data with this certain code required by system that is connect at Parallel Port PC if paper have [used up/finished] or not been attached carefully. After initialization process completed, hence program will be awaiting existence of signal strobe from Parallel Port PC indicating that data has made ready. DST-51 will take the data through Port 1 after signal strobe emerges and continued with delivery of data serially passed the serial port. During delivery of serial data, PC is not permitted sends the next data, therefore condition of busy must be set by activating pin busy beforehand.
After data is sent in asynchronous through serial port, condition of busy expressed completed and program to return to best awaiting signal appearance strobe. Port Parallel PC detecting completed of condition of busy will send the next data by accompanied by signal strobe.
Serial part of interrupt is done by if system that is connecting at printer sends feedback serially asynchronous also through media infrared. At the time of feedback happened hence main program will be desisted and implements serial part of interrupt. Need to be paid attention position of transmitter and acceptor infrared which connecting at transmitter system (system that is connect with Parallel Port PC) that radiation infrared is not about his own acceptor so that continuous program of interrupted when data delivery.
In serial part of interrupt, serial data entering will be verified beforehand, if the data is errors cartridge code hence delivery of data from Parallel Port to PC must be stopped with men-set condition of pin PE. The condition defended finite of cartridge code ready sent by acceptor system (system that is connect at printer)
