xr17d152im Exar Corporation, xr17d152im Datasheet - Page 9

• Manufacturer Part Number: xr17d152im
• Description: Universal 3.3v And 5v Pci Bus Dual Uart
• Manufacturer: Exar Corporation

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REV. 1.2.0
The XR17D152 UART has three different sets of registers as shown in
configuration space registers are for plug-and-play auto-configuration when connecting the device to the PCI
bus. This auto-configuration feature makes installation very easy into a PCI system and it is part of the PCI
local bus specification. The second register set is the device configuration registers that are accessible directly
from the PCI bus for programming general operating conditions of the device and monitoring the status of
various functions. These registers are mapped into 1K of the PCI bus memory address space. These functions
include both channel UART’s interrupt control and status, 16-bit general purpose timer control and status,
multipurpose inputs/outputs control and status, sleep mode, soft-reset, and device identification and revision.
And lastly, each UART channel has its own set of 5G internal UART configuration registers for its own operation
control and status reporting. Both sets of channel registers are embedded inside the device configuration
registers space, which provides faster access. The following paragraphs describe all 3 sets of registers in
detail.
F
2.0 XR17D152 REGISTERS
IGURE
5. T
Device Configuration and
Registers are mapped on
UART[1:0] Configuration
byte of memory address
Register (BAR) in a 1K-
PCI Local Bus
to the Base Address
HE
Interface
Target
XR17D152 R
space
EGISTER
S
ETS
Configuration Space
Registers for Plug-
PCI Local Bus
and-Play Auto
TIMER, REG
Configuration
Channel 0
Channel 0
Channel 1
INT, MPIO,
9
UNIVERSAL (3.3V AND 5V) PCI BUS DUAL UART
0x03FF
0x0000
0x0080
0x0100
0x0200
and Product Model Number
Vendor and Sub-vendor ID
in External EEPROM
Device Configuration Registers
16550 Compatible and EXAR
Sleep, Reset, DVID, DREV
Global Source Interrupt,
UART[1:0] Configuration
16-bit Timer/Counter,
Figure
Enhanced Registers
Multipurpose I/Os,
Registers
5. The PCI local bus
152REGS
XR17D152