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Table 71 – X-Bus, Logical Device 8 [Logical Device Number = 0x08]
REG INDEX
Base I/O Address 3
– High Byte
Default = 0x00
on VTR POR, VCC
POR, Hard Reset
and Soft Reset
Address 3 –
Low Byte
Register
bit[1]=1
Base I/O Address 3
– Low Byte
Default = 0x00
on VTR POR, VCC
POR, Hard Reset
and Soft Reset
Bit 1 is reset on
VCC POR, VTR
POR and Hard
Reset
0=enable chip select
1=disable chip select
X-Bus Selection
Default = 0x00
on VTR POR
Bit 7 is reset on
VCC POR, VTR
POR and Hard
Reset
These bits select the pulse width of the X-bus read
and write strobes. They extend the LPC cycle
accordingly by adding wait states (sync fields) into the
cycle.
11=540nsec min
10=420nsec min
01=300nsec min
00=180nsec min (default)
Bits[6:4] Reserved
Bit[7] Register Write Protect. Cleared by VCC POR,
VTR POR and Hard Reset only. Cannot be cleared by
software writing this bit.
0=X-Bus selection register is Read/Write.
1=X-Bus Selection register is Read-Only
Note 1: If the I/O Base Address of the logical device is not within the Base I/O range as shown in the
Logical Device I/O map, then read or write is not valid and is ignored.
NAME
DEFINITION
STATE
0x66
R/W,
Read-Only
when the
Base I/O
Register 0x66 sets the high byte of the base I/O address
for chip select 3. This register is only used in X-Bus
Mode 1.
Bits [7:0] =address[15:8]
Note: Bits[15:12] must be ‘0’ since the chip performs 16-
bit address qualification on the base I/O addresses.
0x67
R/W,
Read-Only
when the
Base I/O
Address 3 –
Low Byte
Register
bit[1]=1
Register 0x67 sets the low byte of the base I/O address
for chip select 3. Bit 1 is the write protect bit for
registers 66 and 67. Bit 0 is the disable bit for nXCS3.
This register is only used in X-Bus Mode 1.
Bits [7:2] =address[7:2]
Bit[1] = Register 66, 67 Write Protect. Cleared by VCC
POR and Hard Reset only. Cannot be cleared by
software writing to this bit.
0=Register 66 and 67 are read/write
1=Register 66 and 67 are read-only
Bit[0] = Disable bit for nXCS3.
0xF0
(R/W)
Bit[0] X-Bus Mode.
0=Mode 1
1=Mode 2
Note that the GPIOs must be configured properly to
use the selected mode. The GPIOs are not
automatically configured for the mode selected.
Bit[1] Reserved
Bits[3:2] X-Bus Read/Write Pulse Width Selection.