Fujitsu MHZ2250BJ Manuel d'utilisateur Page 256

  • Télécharger
  • Ajouter à mon manuel
  • Imprimer
  • Page
    / 320
  • Table des matières
  • MARQUE LIVRES
  • Noté. / 5. Basé sur avis des utilisateurs
Vue de la page 255
Interface
5.4.4 DMA data-in command protocol
DMA data-in commands include the following commands:
READ DMA (EXT)
IDENTFY DEVICE DMA
READ LOG DMA EXT
The DMA mechanism transfers data of more than one block from the device to the
host. The completion of a command is reported by an interruption.
An outline of this protocol is as follows:
1) The device receives a DMA data-in command with the RegHD FIS.
2) If an error remaining in the device prevents command execution, the device
sends the RegDH FIS with 1 set in the I bit.
3) When the device is ready to send data, it sends the Data FIS to the host.
4) When all data has been transferred, the device sends the RegDH FIS (with 1
set in the I bit) to complete execution of the command. If any data remains to
be sent by the device, this protocol is repeated starting from step 3). (The
maximum data size is 8 KB.)
Device
Host
RegHD
DATA
RegDH
Figure 5.16 DMA data-in command protocol
5-182 C141-E280
Vue de la page 255
1 2 ... 251 252 253 254 255 256 257 258 259 260 261 ... 319 320

Commentaires sur ces manuels

Pas de commentaire