XR17C158CV-F Exar Corporation, XR17C158CV-F Datasheet - Page 15

• Manufacturer Part Number: XR17C158CV-F
• Description: IC UART PCI BUS 5V OCTAL 144LQFP
• Manufacturer: Exar Corporation
• Type: Universal PCI Bus Octal UARTr

Specifications of XR17C158CV-F

• Number Of Channels: 8
• Package / Case: 144-LQFP
• Features: *
• Fifo's: 64 Byte
• Protocol: RS485
• Voltage - Supply: 5V
• With Auto Flow Control: Yes
• With Irda Encoder/decoder: Yes
• With False Start Bit Detection: Yes
• With Modem Control: Yes
• Mounting Type: Surface Mount
• Data Rate: 6.25 Mbps
• Supply Voltage (max): 7 V
• Supply Current: 5 mA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Operating Supply Voltage: 7 V
• No. Of Channels: 8
• Uart Features: High Performance, Read/Write Burst Operation
• Supply Voltage Range: -0.5V To 7V
• Operating Temperature Range: 0°C To +70°C
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: 1016-1287

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REV. 1.4.3
The XR17C158 has a 32-bit wide register [INT0, INT1, INT2 and INT3] to provide interrupt information and
supports two interrupt schemes. The first scheme is an 8-bit indicator representing all 8 channels with each bit
representing each channel from 0 to 7. This permits the interrupt routine to quickly vector and serve that UART
channel and determine the source(s) in each individual routines. INT0 bit-0 represents the interrupt status for
UART channel 0 when its transmitter, receiver, line status, or modem port status requires service. Other bits in
the INT0 register provide indication for the other channels with bit-7 representing UART channel 7 respectively.
The second scheme provides detail about the source of the interrupts for each UART channel. All the interrupts
are encoded into a 3-bit code. This 3-bit code represents 7 interrupts corresponding to individual UART’s
transmitter, receiver, line status, modem port status. INT1, INT2 and INT3 registers provide the 24-bit interrupt
status for all 8 channels. Bits 8, 9 and 10 representing channel 0 and bits 29, 30 and 31 representing channel 7
respectively. All 8 channel interrupts status are available with a single DWORD read operation. This feature
allows the host to quickly vector and serve the interrupts, reducing service interval, hence, reducing the host
bandwidth requirement.
A special interrupt condition is generated by the 158 when it wakes up from sleep mode. This special interrupt
is cleared by reading the INT0 register. If there are not any other interrupts pending, the value read from INT0
would be 0x00.
INT0 [7:0] Channel Interrupt Indicator
Each bit gives an indication of the channel that has requested for service. Bit-0 represents channel 0 and bit-7
indicates channel 7. Logic 1 indicates that a channel has called for service. The interrupt bit clears after
reading the appropriate register of the interrupting channel register, see Interrupt Clearing section.
INT3, INT2 and INT1 [32:8]
Twenty four bit encoded interrupt indicator. Each channel’s interrupt is encoded into 3 bits for receive, transmit,
and status. Bits [10:8] represent channel 0 and go up to channel 7 with bits [31:29]. The 3 bit encoding and
their priority order are shown below in
they only exist within the channel 0 space (bits [10:8]) and not in any other channel.
1.2.1
The Interrupt Status Register
GLOBAL INTERRUPT REGISTER (DWORD)
INT3 [31:24]
Figure 4
The INT0 register provides individual status for each channel
Bit-7 Bit-6 Bit-5 Bit-4 Bit-3 Bit-2 Bit-1 Bit-0
Ch-7
shows the 4-byte interrupt register and its make up.
Individual UART Channel Interrupt Status
Ch-6
Table
INT2 [23:16]
Ch-5 Ch-4 Ch-3 Ch-2 Ch-1 Ch-0
5. The Timer and MPIO interrupts are for the device and therefore
INT0 Register
15
INT1 [15:8]
[default 0x00-00-00-00]
INT0 [7:0]
5V PCI BUS OCTAL UART
XR17C158