Difference between revisions of "83Plus:Ports:08"

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(Added interrupt info)
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=== Read Values ===
 
=== Read Values ===
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* Bit 1: 1 if link assist will generate an interrupt when a byte is received.(Link assist must be enabled)
 
* Bit 7: 1 if the link assist is disabled.
 
* Bit 7: 1 if the link assist is disabled.
  
 
=== Write Values ===
 
=== Write Values ===
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* Bit 1: Set to generate an interrupt when link assist receives a byte.(Link assist must be enabled)
 
* Bit 7: 1 to disable the link assist.
 
* Bit 7: 1 to disable the link assist.
  
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Programs which directly control the link port should disable the hardware assist.
 
Programs which directly control the link port should disable the hardware assist.
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 +
===Interrupts===
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Link Assist hardware can generate an interrupt when a byte is recieved. To enable this write 01 to port 08. When a byte recieved and an interrupt is generated bit 0 of port 9 is set. Like all interrupts this one needs to be acknowledged, do this by reading the byte from port 0A.
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== Credits and Contributions ==
 
== Credits and Contributions ==
 
* '''Michael Vincent:''' Original documentation of the link assist
 
* '''Michael Vincent:''' Original documentation of the link assist

Revision as of 18:21, 22 July 2005

Synopsis

Port Number: 08h

Function: Link Assist Enable

This port controls whether the hardware link assist is enabled.

Read Values

  • Bit 1: 1 if link assist will generate an interrupt when a byte is received.(Link assist must be enabled)
  • Bit 7: 1 if the link assist is disabled.

Write Values

  • Bit 1: Set to generate an interrupt when link assist receives a byte.(Link assist must be enabled)
  • Bit 7: 1 to disable the link assist.

Comments

This port only exists on the 83+ SE and the 84+.

Programs which directly control the link port should disable the hardware assist.

Interrupts

Link Assist hardware can generate an interrupt when a byte is recieved. To enable this write 01 to port 08. When a byte recieved and an interrupt is generated bit 0 of port 9 is set. Like all interrupts this one needs to be acknowledged, do this by reading the byte from port 0A.


Credits and Contributions

  • Michael Vincent: Original documentation of the link assist