Zilog Z08470 Manual de usuario Pagina 220

  • Descarga
  • Añadir a mis manuales
  • Imprimir
  • Pagina
    / 330
  • Tabla de contenidos
  • MARCADORES
  • Valorado. / 5. Basado en revisión del cliente
Vista de pagina 219
UM008101-0601 Parallel Input/Output
If more than four PIO devices must be accommodated, a look-ahead struc-
ture may be used as shown in Figure 14. With this technique, more than
thirty PIOs may be chained together using standard TTL logic.
Figure 14. A Method of Extending the Interrupt Priority Daisy-Chain
I/O Device Interface
In this example, the Z80 PIO is connected to an I/O terminal device, which
communicates over an 8-bit parallel bidirectional data bus as illustrated in
Figure 15. Mode 2 operation (bidirectional) is selected by sending the
following control word to Port A:
Next, the appropriate interrupt vector is loaded (refer to Z80 CPU Users
Manual for details on the operation of the interrupt).
Z80
CPU
IEOIEI IEOIEI
IEOIEI IEOIEI
Data Bus
+V
PI0
PI0 PI0
PI0
IEOIEI
IEOIEI
IEOIEI
IEOIEI
PI0
PI0 PI0 PI0
Mode Control
XX
D7 D6 D5 D4 D3 D0D2 D1
11 11
10
Vista de pagina 219
1 2 ... 215 216 217 218 219 220 221 222 223 224 225 ... 329 330

Comentarios a estos manuales

Sin comentarios