Seagate ST3660A Product Manual - Page 35

Medalist XE Family Product Manual, Rev. B 27 3.3.2.1 PIO and DMA Data Transfer Modes You can use the Set Features command to set the type of data transfer mechanism and transfer mode that the drive uses. To do this: 1. Write Set Features command value 03H (Set Data Transfer mode) to the Features register. 2. Write a Transfer Types value to the Sector Count register. The upper 5 bits of this value define the type of data transfer, and the lower 3 bits encode the mode value. The following table identifies allowable Transfer Types values: Data Transfer Mechanism Mechanism name Mode value PIO Transfer Mode (default: Set PIO Mode = 2) 2 PIO Transfer Mode: Set PIO Mode = 2 2 PIO Flow Control Transfer Mode: Set PIO Mode = 0 0 PIO Flow Control Transfer Mode: Set PIO Mode = 1 1 PIO Flow Control Transfer Mode: Set PIO Mode = 2 2 PIO Flow Control Transfer Mode: Set PIO Mode = 3 3 Multiword DMA Mode 0 Multiword DMA Mode 1 Reserved - Transfer Types value Data Upper 5 bits Lower 3 bits 00000 000 00000 001 00001 000 00001 001 00001 010 00001 011 00100 000 00100 001 01000 nnn Notes: 1. If the drive does not support a commanded mode, the drive returns an Aborted Command error. 2. If the drive receives a Set Features command with a Mechanism and mode value of 00000 001 and the drive supports disabling of IORDY, then the drive sets its default PIO transfer mode and disables IORDY. Reserved values are intended for use in a future specification of an alternative flow-control mechanism.