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Set Up
Register
Host
Block
Drive
DRDY
BSY
DRQ
INTRQ
Figure 11-5. Timing Diagram—PIO Read Command (Class 1)
11.7.4.1.2
Class 2—PIO Write
The PIO single sector write command [format, write buffer, write sector(s)] is as follows:
1.
HOST: Write to ATA control/command block registers to setup for data write.
2.
HOST: Write to ATA command register to execute write command.
3.
HOST: Poll drive to see if it is ready.
4.
HOST: Write ATA data register 256 times to get all 512Bytes into sector buffer.
5.
DRIVE: When sector buffer is filled, write sector to physical medium.
6.
DRIVE: Interrupt HOST when done.
7.
HOST: Read ATA control/command block registers to get status.
8.
DRIVE: Clear interrupt after reading status register.
9.
Repeat steps 4–8 for multiple sector writes.
The PIO block mode write command (write multiple) is as follows:
1.
HOST: Write to ATA control/command block registers to set up for data write.
2.
HOST: Write to ATA command register to execute write command.
3.
HOST: Poll drive to see if it is ready.
4.
HOST: Write ATA data register 256 times to get all sectors into sector buffer.
5.
DRIVE: When sector buffer is filled, write sector to physical medium.
6.
DRIVE: Interrupt HOST when done.
7.
HOST: Read ATA control/command block registers to get status.
8.
DRIVE: Clear interrupt after reading status register.
Figure 11-6
shows the PIO Write process.
Freescale Semiconductor
Send
Read
Command
Status
Read
Sector
MPC5200B Users Guide, Rev. 1
Read
Read
Sector
Status
Buffer
Read
Sector
ATA Bus Background
Read
Sector
Buffer
11-31
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