The Parallel Port: Termination of a 1284 Mode
Byte and Nibble Mode Termination |
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A 1284 compliant peripheral device must implement this sequence.
For EPP mode termination and ECP mode termination are different. The following diagram shows the standard termination sequence for byte and nibble modes.
| /Select | /AutoFeed | /Ack | |||||||||||||||
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| 1284Active | HostBusy | PtrClk | |||||||||||||||
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| 1 |
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H signals begin of termination sequence | |||||||||||||
| 2 |
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P signals acknowlegdement | |||||||||||||
| 3 |
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H signals end of termination sequence | |||||||||||||
| 4 |
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P signals acknowlegdement | |||||||||||||
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| 5 |
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H sets /AutoFeed to desired value | |||||||||||||
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H and P are now in compatibilily mode again | ||||||||||||||
EPP Termination |
※ |
This termination sequence is quite trivial and can probably terminate byte and nibble modes, too, because it uses the /Init line, which should reset the printer. Only in ECP mode, this does not work, since ECP uses the /Init line as a normal signal.
| /Init | /Select | |||||||||||
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| 1284Active | ||||||||||||
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| 1 |
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H signals begin of termination sequence | |||||||||
| 2 |
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H waits for >=50us | |||||||||
| 3 |
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H selects device | |||||||||
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H and P are now in compatibilily mode again | ||||||||||
