83Plus:Ports:09

Synopsis

Port Number: 09h

Function: Link Assist Status

This port gives information on the status of the hardware link assist.

Read Values

• Bit 0: Set if an interrupt was generated by receiving a byte.
• Bit 1: Set if an interrupt was generated when a byte can be sent.
• Bit 2: Set if an interrupt was generated due to an error in transmission.
• Bit 3: Set if the assist is currently receiving data
• Bit 4: Set if the assist has read a complete byte (which can be read from port 0A)
• Bit 5: Set if the assist is ready to write data (via port 0D)
• Bit 6: Set if there was an error during transmission
• Bit 7: Set if the link assist is currently sending a byte.

Write Values

None

Comments

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

Credits and Contributions

• Michael Vincent: Original documentation of the link assist