WinSystems LBC- 486Plus, Руководство по эксплуатации

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Bits 5-0 al low for lock ing the I/O ports. A '1' writ ten to the I/O port po si tion will pro hibit fur ther
writes to the cor re spond ing I/O port.
POL0- POL2 - These reg is ters are ac ces si ble when page 1 is se lected. They al low in ter rupt po lar ity
se lec tion on a port- by- port and bit- by- bit ba sis. Writ ing a '1' to a bit po si tion se lects the ris ing edge de -
tec tion in ter rupts while writ ing a '0' to a bit po si tion se lects fal ling edge de tec tion in ter rupts.
ENAB0- ENAB2 - These reg is ters are ac ces si ble when page 2 is se lected. They al low for port- by-
port and bit- by- bit ena bling of the edge de tec tion in ter rupts. When set to a '1' the edge de tec tion in ter -
rupt is en abled for the cor re spond ing port and bit. When cleared to a '0' the bit's edge de tec tion in ter rupt
is dis abled. Note that this reg is ter can be used to in di vidu ally clear a pend ing in ter rupt by dis abling and
reena bling the pend ing in ter rupt.
INT_ID0 - INT_ID2 - These reg is ters are ac ces si ble when page 3 is se lected. They are used to
iden tify cur rently pend ing edge in ter rupts. A bit when read as a '1' in di cates that an edge of the po lar ity
pro grammed into the cor re spond ing po lar ity reg is ter has been rec og nized. Note that a write to this reg
-
is ter (value ig nored) clears ALL of the pend ing in ter rupts in this reg is ter.
2.21
VGA Con figu ra tion
Page 2 - 24 OPERATIONS MANUAL LBC-Plus 991206
WinSystems - "The Embedded Systems Authority"
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