ST16C654IQ64-F Exar Corporation, ST16C654IQ64-F Datasheet - Page 15

• Manufacturer Part Number: ST16C654IQ64-F
• Description: IC UART FIFO 64B QUAD 64LQFP
• Manufacturer: Exar Corporation
• Type: Quad UART with 16-byte FIFOsr

Specifications of ST16C654IQ64-F

• Number Of Channels: 4, QUART
• Package / Case: 64-LQFP
• Features: *
• Fifo's: 64 Byte
• Protocol: RS232
• Voltage - Supply: 2.97 V ~ 5.5 V
• With Auto Flow Control: Yes
• With Irda Encoder/decoder: Yes
• With False Start Bit Detection: Yes
• With Modem Control: Yes
• With Cmos: Yes
• Mounting Type: Surface Mount
• Data Rate: 1.5 Mbps
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2.97 V
• Supply Current: 3 mA to 6 mA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 45 C
• Mounting Style: SMD/SMT
• Operating Supply Voltage: 2.97 V to 5.5 V
• No. Of Channels: 4
• Uart Features: Infrared (IrDA) Encoder/Decoder
• Supply Voltage Range: 2.97V To 5.5V
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case Style: LQFP
• 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: 1016-1273

xr
ST16C654/654D
2.97V TO 5.5V QUAD UART WITH 64-BYTE FIFO
REV. 5.0.2
2.10
Receiver
The receiver section contains an 8-bit Receive Shift Register (RSR) and 64 bytes of FIFO which includes a
byte-wide Receive Holding Register (RHR). The RSR uses the 16X 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 clock rate. After 8 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 2-4. Upon unloading the receive data byte from RHR, the
receive FIFO pointer is bumped and the error tags 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 interrupt when data is not received for 4 word lengths as defined by LCR[1:0] plus 12 bits time. This is
equivalent to 3.7-4.6 character times. The RHR interrupt is enabled by IER bit-0.
2.10.1
Receive Holding Register (RHR) - Read-Only
The Receive Holding Register is an 8-bit register that holds a receive data byte from the Receive Shift
Register. It provides the receive data interface to the host processor. The RHR register is part of the receive
FIFO of 64 bytes by 11-bits wide, the 3 extra bits are for the 3 error tags to be reported in LSR register. When
the FIFO is enabled by FCR bit-0, the RHR contains the first data character received by the FIFO. After the
RHR is read, the next character byte is loaded into the RHR and the errors associated with the current data
byte are immediately updated in the LSR bits 2-4.
F
9. R
O
-FIFO M
IGURE
ECEIVER
PERATION IN NON
ODE
16X Clock
Receive Data Shift
Data Bit
Register (RSR)
Validation
Receive Data Characters
Error
Receive
Receive Data
Tags in
Data Byte
RHR Interrupt (ISR bit-2)
Holding Register
LSR bits
and Errors
(RHR)
4:2
RXFIFO1
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