Toshiba 4006GAH Manual Do Utilizador

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10.8.23  Read DMA  (C8h/C9h) 
 
COMMAND CODE 
1 1 0 0 1 0 0 X
REGISTER 
 
REGISTER SETTING 
NORMAL COMPLETION 
DR 
drive no. 
no change 
CY 
starting cylinder 
last possible 
HD 
starting head 
last possible 
SN 
starting sector 
last possible 
SC 
no. of sector to read 
00H 
FT  
no 
change 
LBA 
staring address 
last address 
 
This command is basically identical to Sector command except following features. 
• 
Host initialize the DMA channel before issuing command. 
- Data transfer is initiated by DMARQ and handled by the DMA channel in the host. 
- Drive issues only one interrupt at the completion of each command to show the status is valid after data 
transfer. 
 
During DMA transfer phase, either BSY or DRQ is set to 1. 
When a command is completed, CY, HD, SN register (LBA register) shows the sector transferred the latest. 
 
If the drive detects unrecoverable error, the drive terminate the command and CY, HD, SN register (LBA 
register) shows the sector where error occurred. 
 
10.8.24  Read DMA EXT    (25h) 
 
COMMAND CODE 
0 0 1 0 0 1 0 1
 
REGISTER 
 
REGISTER SETTING 
NORMAL COMPLETION 
DR 
 
drive no. 
no change 
LBA 
Low 
Current 
Previous 
LBA(7:0) 
LBA(31:24) 
HOB=0
HOB=1
last address 
last address 
LBA 
Mid 
Current 
Previous 
LBA(15:8) 
LBA(39:32) 
HOB=0
HOB=1
last address 
last address 
LBA 
High 
Current 
Previous 
LBA(23:16) 
LBA(47:40) 
HOB=0
HOB=1
last address 
last address 
SC Current 
Previous 
sector count(7:0) 
sector count(15:8) 
HOB=0
HOB=1
00H 
00H 
FT Current 
Previous 
reserved 
reserved 
HOB=0
HOB=1
no change 
no change 
 
This command is basically identical to Read DMA command except register setting.   
This command is available in LBA addressing only.