xr16l2750im Exar Corporation, xr16l2750im Datasheet - Page 9

• Manufacturer Part Number: xr16l2750im
• Description: High-performance 2.25v - 5.5v Duart
• Manufacturer: Exar Corporation

xr
REV. 1.2.1
The INTA and INTB interrupt output changes according to the operating mode and enhanced features setup.
Table 3 and 4
through
The 2750 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. Please note that the input XTAL1 is not
5V tolerant and so the maximum at the pin should be VCC. For programming details, see “Programmable
Baud Rate Generator.”
2.8
2.9
INTA/B Pin
INTA/B Pin
INTA/B Pin
INTA and INTB Outputs
Crystal Oscillator or External Clock Input
23.
summarize the operating behavior for the transmitter and receiver. Also see
A
LOW = no data
HIGH = 1 byte
UTO
M
YES
NO
ODE
RS485
(FIFO D
T
FCR B
ABLE
T
ABLE
LOW = a byte in THR
HIGH = THR empty
LOW = a byte in THR
HIGH = transmitter empty
IT
ISABLED
F
3: INTA
-0 = 0
IGURE
4: INTA
(FIFO D
FCR B
)
4. T
AND
AND
22-47 pF
IT
ISABLED
YPICAL OSCILLATOR CONNECTIONS
XTAL1
INTB P
-0 = 0
C1
LOW = FIFO below trigger level
HIGH = FIFO above trigger level
INTB P
500 ΚΩ − 1 ΜΩ
)
INS
R2
IN
22-47 pF
9
XTAL2
O
C2
O
Y1
PERATION FOR
LOW = FIFO above trigger level
HIGH = FIFO below trigger level or FIFO empty
LOW = FIFO above trigger level
HIGH = FIFO below trigger level or transmitter empty
PERATION
1.8432 MHz
(Optional)
0-120 Ω
24 MHz
2.25V TO 5.5V DUART WITH 64-BYTE FIFO
R1
to
F
FCR B
OR
(FIFO E
FCR B
T
RANSMITTER
R
ECEIVER
IT
-0 = 1 (FIFO E
IT
NABLED
-0 = 1
)
NABLED
)
XR16L2750
Figures 18