XR17C158CV-F Exar Corporation, XR17C158CV-F Datasheet - Page 30

• 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

XR17C158
5V PCI BUS OCTAL UART
The receiver section contains an 8-bit Receive Shift Register (RSR) and Receive Holding Register (RHR). The
RSR uses the 16X or 8X clock for timing. It verifies and validates every bit on the incoming character in the
middle of each data bit. On the falling edge of a start or false start bit, an internal receiver counter starts
counting at the 16X or 8X clock rate. After 8 or 4 clocks the start bit period should be at the center of the start
bit. At this time the start bit is sampled and if it is still a logic 0 it is validated. Evaluating the start bit in this
manner prevents the receiver from assembling a false character. The rest of the data bits and stop bits are
sampled and validated in this same manner to prevent false framing. If there were any error(s), they are
reported in the LSR register bits 1-4. Upon unloading the receive data byte from RHR, the receive FIFO pointer
is bumped and the error flags are immediately updated to reflect the status of the data byte in RHR register.
RHR can generate a receive data ready interrupt upon receiving a character or delay until it reaches the FIFO
trigger level. Furthermore, data delivery to the host is guaranteed by a receive data ready time-out function
when receive data does not reach the receive FIFO trigger level. This time-out delay is 4 word lengths as
defined by LCR[1:0] plus 12 bits time. The RHR interrupt is enabled by IER bit-0.
The receive holding register is an 8-bit register that holds a receive data byte from the receive shift register
(RSR). It provides the receive data interface to the host processor. The host reads the receive data byte on this
register whenever a data byte is transferred from the RSR. RHR also part of the receive FIFO of 64 bytes by
11-bit wide, 3 extra bits are for the error flags to be in LSR register. When the FIFO is enabled by FCR bit-0, it
acts as the first-out register of the FIFO as new data are put over the first-in register. The receive FIFO pointer
is bumped after the RHR register is read. Also, the error flags associated with the data byte are immediately
updated onto the line status register (LSR) bits 1-4.
4.3
4.3.1
F
IGURE
Receiver
(8XMODE Register)
11. T
(Xoff1/2 and Xon1/2 Reg.
Auto Software Flow Control
Auto CTS Flow Control (CTS# pin)
Flow Control Characters
Receive Holding Register (RHR) - Read-Only
16X or 8X Clock
RANSMITTER
Data Byte
O
Transmit
PERATION IN
FIFO
Transmit Data Shift Register
AND
(64-Byte)
Transmit
F
FIFO
(TSR)
LOW
30
C
ONTROL
M
THR Interrupt (ISR bit-1) falls
ODE
when becomes empty. FIFO
below Programmed Trigger
is Enabled by FCR bit-0=1
Level (TXTRG) and then
xr
TXFIFO1
REV. 1.4.3