Intel 386 Manual do Utilizador Página 223

  • Descarregar
  • Adicionar aos meus manuais
  • Imprimir
  • Página
    / 691
  • Índice
  • MARCADORES
  • Avaliado. / 5. Com base em avaliações de clientes
Vista de página 222
Intel386™ EX EMBEDDED MICROPROCESSOR USERS MANUAL
9-24
9.3.6 Initialization Command Word 4 (ICW4)
Use ICW4 to select the special-fully nested mode or the fully nested mode and to enable the au-
tomatic EOI mode.
Figure 9-12. Initialization Command Word 4 Register (ICW4)
Initialization Command Word 4
ICW4 (master and slave)
(write only)
Expanded Addr:
ISA Addr:
Reset State:
master slave
F021H F0A1H
0021H 00A1H
XXH XXH
7 0
000SFNM00AEOI1
Bit
Number
Bit
Mnemonic
Function
7–5 Write zero to these bits to guarantee device operation.
4 SFNM Special-fully Nested Mode:
0 = Selects fully nested mode.
1 = Selects special-fully nested mode. Only the master 82C59A can
operate in special-fully nested mode.
3–2 Write zero to these bits to guarantee device operation.
1 AEOI Automatic EOI Mode:
0 = Disables automatic EOI mode.
1 = Enables automatic EOI mode. Only the master 82C59A can operate
in automatic EOI mode.
0 Write one to this bit to guarantee device operation.
Vista de página 222
1 2 ... 218 219 220 221 222 223 224 225 226 227 228 ... 690 691

Comentários a estes Manuais

Sem comentários