
                                CMD646 Chipset.
--------------- Primary Channel ---------------- Secondary Channel -------------
                 enabled                          enabled
--------------- drive0 --------- drive1 -------- drive0 ---------- drive1 ------
DMA enabled:    no               no              no                no 
UDMA enabled:   no               no              no                no 
UDMA enabled:   4                4               4                 4
DMA enabled:    2                2               2                 2
PIO
ARTTIM0   = 0x40, HI = 0x04, LOW = 0x00
DRWTIM0   = 0x3f, HI = 0x03, LOW = 0x0f
ARTTIM1   = 0x40, HI = 0x04, LOW = 0x00
DRWTIM1   = 0x3f, HI = 0x03, LOW = 0x0f
ARTTIM23  = 0x4c, HI = 0x04, LOW = 0x0c
DRWTIM2   = 0x3f, HI = 0x03, LOW = 0x0f
DRWTIM3   = 0x3f, HI = 0x03, LOW = 0x0f
UDIDETCR0 = 0xf0, HI = 0x0f, LOW = 0x00
UDIDETCR1 = 0xf0, HI = 0x0f, LOW = 0x00
