XR17D152 Datasheet, PDF (9/68 Pages) Exar Corporation – UNIVERSAL (3.3V AND 5V) PCI BUS DUAL UART

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REV. 1.2.0
XR17D152
UNIVERSAL (3.3V AND 5V) PCI BUS DUAL UART
2.0 XR17D152 REGISTERS
The XR17D152 UART has three different sets of registers as shown in Figure 5. The PCI local bus
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.
FIGURE 5. THE XR17D152 REGISTER SETS
Device Configuration and
UART[1:0] Configuration
Registers are mapped on
to the Base Address
Register (BAR) in a 1K-
byte of memory address
space
PCI Local Bus
Target
Interface
PCI Local Bus
Configuration Space
Registers for Plug-
and-Play Auto
Configuration
Vendor and Sub-vendor ID
and Product Model Number
in External EEPROM
Channel 0
INT, MPIO,
TIMER, REG
Channel 0
Channel 1
0x0000
0x0080
0x0100
0x0200
0x03FF
Device Configuration Registers
Global Source Interrupt,
Multipurpose I/Os,
16-bit Timer/Counter,
Sleep, Reset, DVID, DREV
UART[1:0] Configuration
Registers
16550 Compatible and EXAR
Enhanced Registers
152REGS
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