Host Interface
4.3.1.5 Drive Address register
This register's bits are defined as shown below.
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| Table 4.6 Bit definitions of Drive Address register |
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7 | 6 |
| 5 | 4 | 3 | 2 | 1 |
| 0 |
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HiZ | nWTG |
| nHS3 | nHS2 | NhS1 | nHS0 | nDS1 |
| nDS0 | Read |
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HiZ is always in the
nWTG indicates the status of the ODD internal data write control signal (Write Gate).
nHS3 indicates a binary complement of bits 3 to 0 of the drive select register.
nDS1 is the device select bit for device 1. It is 0 when device 1 is selected.
nDS0 is the device select bit for device 0. It is 0 when device 0 is selected.
4.3.1.6 ATAPI Byte Count register
This register's bits are defined as shown below.
Table 4.7 Bit definitions of ATAPI Byte Count register
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
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Byte Count (Bits
Byte Count (Bits
R/W
R/W
•This register is used for PIO transfer only. The ODD sets the byte count to be transferred by the host in this register and sets DRQ to 1. The ODD does not update this register until transfer starts.