xr16c2552ij Exar Corporation, xr16c2552ij Datasheet - Page 9

• Manufacturer Part Number: xr16c2552ij
• Description: 2.97v To 5.5v Dual Uart With 16-byte Fifo
• Manufacturer: Exar Corporation

xr
REV. 1.0.0
The INTA and INTB interrupt outputs change according to the operating mode and enahnced features setup.
Tables
through 21.
The 2552 includes an on-chip oscillator (XTAL1 and XTAL2) to produce a clock for both UART sections in the
device. The CPU data bus does not require this clock for bus operation. The crystal oscillator provides a
system clock to the Baud Rate Generators (BRG) section found in each of the UART. XTAL1 is the input to the
oscillator or external clock buffer input with XTAL2 pin being the output.
Generator” on page 10.
F
The on-chip oscillator is designed to use an industry standard microprocessor crystal (parallel resonant,
fundamental frequency with 10-22 pF capacitance load, ESR of 20-120 ohms and 100ppm frequency
tolerance) connected externally between the XTAL1 and XTAL2 pins (see
1 M
baud rate generator for standard or custom rates. Typical oscillator connections are shown in
further reading on oscillator circuit please see application note DAN108 on EXAR’s web site.
2.7
2.8
IGURE
INTA/B Pin
INTA/B Pin
resistor across it. Alternatively, an external clock can be connected to the XTAL1 pin to clock the internal
3 and 4
4. T
INTA and INTB Ouputs
Crystal Oscillator or Ext. Clock Input
YPICAL OSCILLATOR CONNECTIONS
0 = a byte in THR
1 = THR empty
0 = no data
1 = 1 byte
summarize the operating behavior for the transmitter and receiver. Also see Figures
(FIFO D
(FIFO D
FCR B
FCR B
T
ABLE
T
IT
ISABLED
IT
ISABLED
ABLE
-0 = 0
-0 = 0
3: INTA
4: INTA
)
)
AND
AND
0 = FIFO below trigger level
1 = FIFO above trigger level
22-47 pF
XTAL1
INTB P
0 = at least 1 byte in FIFO
1 = FIFO empty
C1
INTB P
INS
R2
22-47 pF
XTAL2
IN
9
C2
O
Y1
O
PERATION FOR
2.97V TO 5.5V DUAL UART WITH 16-BYTE FIFO
PERATION
1.8432 MHz
(Optional)
0-120
24 MHz
R1
to
F
(FIFO E
(FIFO E
OR
FCR B
FCR B
T
RANSMITTER
R
Figure
ECEIVER
IT
IT
NABLED
NABLED
See “Programmable Baud Rate
-0 = 1
-0 = 1
2), with an external 500k
)
)
XR16C2552
Figure
4. For
16
to