XR17D158 Exar Corporation, XR17D158 Datasheet - Page 9

• Manufacturer Part Number: XR17D158
• Description: Eight-channel Pci-bus Uart
• Manufacturer: Exar Corporation

XR17D158
UNIVERSAL (3.3V AND 5V) PCI BUS OCTAL UART
REV. P1.0.0
The XR17D158 will only function properly if VCC (voltage to the UART Core Logic) is greater than or equal to
VIO. For a universal add-in card, it is usually unknown whether it will be plugged into a 3.3V or 5V PCI slot,
therefore VCC must be 5V to guarantee proper functionality in any PCI slot as shown in
embedded system, the designer can choose to use a 5V power supply for the UART core voltage or 3.3V if the
VIO is also at 3.3V. In
system. Also note that when VCC is 3.3V, the maximum PCI clock input frequency is 22MHz.
F
1.0 APPLICATION EXAMPLES
IGURE
3. T
YPICAL
(3.3V or 5V)
(up to 33MHz)
A
VIO
PPLICATION FOR A
CLK
Figure
4, examples 1-3 show valid applications of the XR17D158 in an embedded
Interface
U
Local
Bus
PCI
NIVERSAL
A
DD
M ax Crystal Frequency = 24M Hz
9
-
M ax External Clock = 50MHz
IN
UART Core Logic
C
UART Channel 0
ARD
UART Channel 1
UART Channel 2
UART Channel 3
UART Channel 4
UART Channel 5
UART Channel 6
UART Channel 7
VCC = 5V
PRELIMINARY
áç
áç
áç
áç
Figure
3. In an