Hi,
Inseo> wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 5 (Ultra/100)
Inseo> trap type 200 at 90cdf8
Inseo> panic: trap

I have the same situation with Promise Ultra100TX2/ATA Card,

The kernel is as of 20020526,
NetBSD 1.6_BETA1 (GENERIC) #1: Mon May 27 16:46:47 JST 2002
makoto@ibook:/export/netbsd-1-6/sys/arch/macppc/compile/GENERIC

The Machine here is OF 2.0.2, StarMax 3000/240

(1) Without IDE disk connected to the card,
...
pciide0 at pci0 dev 14 function 0: Promise Ultra100TX2/ATA Bus Master IDE Accelerator (rev. 0x01)
pciide0: bus-master DMA support present
pciide0: primary channel configured to native-PCI mode
pciide0: using irq 24 for native-PCI interrupt
trap type 200 at 34d2d8
Press a key to panic.
panic: trap
Stopped in pid 0 (swapper) at   cpu_Debugger+0x10:      lwz     r0, r1, 0x14
db> trace
db>
... (Nothing displayed)

(2) With IDE disk connected 
...
wd0 at pciide0 channel 0 drive 1: <ST340810A>
wd0: drive supports 16-sector PIO transfers, LBA addressing
wd0: 38166 MB, 16383 cyl, 16 head, 63 sec, 512 bytes/sect x 78165360 sectors
wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 5 (Ultra/100)
trap type 200 at 34d2d8
Press a key to panic.
panic: trap
Stopped in pid 0 (swapper) at   cpu_Debugger+0x10:      lwz     r0, r1, 0x14
db> trace
db> next
After 3 instructions (0 loads, 0 stores),
Stopped in pid 0 (swapper) at   cpu_Debugger+0x1c:      bclr    20, 20,
db> trace
db> next
rebooting

EXIT called

(3) Whole booting message follows: (with disk connnected)

OF_open bootpath=ata/ata-disk@0
read stage 2 blocks: 01234567. done!
starting stage 2...

>> NetBSD/macppc OpenFirmware Boot, Revision 1.6
>> (makoto@ibook, Mon May 27 12:55:46 JST 2002)
3840764+219140 [187936+156045]=0x433514
 start=0x100000
[ using 344596 bytes of netbsd ELF symbol table ]
Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002
    The NetBSD Foundation, Inc.  All rights reserved.
Copyright (c) 1982, 1986, 1989, 1991, 1993
    The Regents of the University of California.  All rights reserved.

NetBSD 1.6_BETA1 (GENERIC) #1: Mon May 27 16:46:47 JST 2002
    makoto@ibook:/export/netbsd-1-6/sys/arch/macppc/compile/GENERIC
total memory = 112 MB
avail memory = 99536 KB
using 1459 buffers containing 5836 KB of memory
no active packagemainbus0 (root)
cpu0 at mainbus0: 603ev (Revision 2.1), ID 0 (primary)
cpu0: HID0 90c001<DOZE,DPM,ICE,DCE,NOPTI>
cpu0: ohare L2 cache enabled
bandit0 at mainbus0
pci0 at bandit0 bus 0
pci0: i/o space, memory space enabled
pchb0 at pci0 dev 11 function 0
pchb0: Apple Computer Bandit Host-PCI Bridge (rev. 0x03)
rtk0 at pci0 dev 13 function 0: RealTek 8139 10/100BaseTX
rtk0: interrupting at irq 23
rtk0: Ethernet address 00:90:cc:2e:a7:57
ukphy0 at rtk0 phy 7: Generic IEEE 802.3u media interface
ukphy0: OUI 0x000000, model 0x0000, rev. 0
ukphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
pciide0 at pci0 dev 14 function 0: Promise Ultra100TX2/ATA Bus Master IDE Accelerator (rev. 0x01)
pciide0: bus-master DMA support present
pciide0: primary channel configured to native-PCI mode
pciide0: using irq 24 for native-PCI interrupt
wd0 at pciide0 channel 0 drive 1: <ST340810A>
wd0: drive supports 16-sector PIO transfers, LBA addressing
wd0: 38166 MB, 16383 cyl, 16 head, 63 sec, 512 bytes/sect x 78165360 sectors
wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 5 (Ultra/100)
trap type 200 at 34d2d8
Press a key to panic.
panic: trap
Stopped in pid 0 (swapper) at   cpu_Debugger+0x10:      lwz     r0, r1, 0x14
db> trace
db> next
After 3 instructions (0 loads, 0 stores),
Stopped in pid 0 (swapper) at   cpu_Debugger+0x1c:      bclr    20, 20,
db> trace
db> next
rebooting

EXIT called
Open Firmware, 2.0.2
To continue booting the MacOS type:
BYE<return>
To continue booting from the default boot device type:
BOOT<return>
 ok
0 >