xr16v2550im Exar Corporation, xr16v2550im Datasheet - Page 9

• Manufacturer Part Number: xr16v2550im
• Description: High Performance Duart With 16-byte Fifo
• Manufacturer: Exar Corporation

REV. 1.0.2
The INTA and INTB interrupt output changes according to the operating mode and enhanced features setup.
Table 3 and 4
through
The V2550 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. For programming details, see
““Section 2.10, Programmable Baud Rate Generator with Fractional Divisor” on page
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 100 ppm frequency
tolerance) connected externally between the XTAL1 and XTAL2 pins (see
Rate Generator is capable of operating with a crystal oscillator frequency of up to 32 MHz at 2.5V. However,
with an external clock input on XTAL1 pin, it can extend its operation up to 64 MHz (16 Mbps serial data rate)
F
2.8
2.9
IGURE
INTA/B Pin
INTA/B Pin
INTA/B Pin
4. T
INTA and INTB Outputs
Crystal Oscillator or External Clock Input
22.
YPICAL
summarize the operating behavior for the transmitter and receiver. Also see
LOW = a byte in THR
HIGH = THR empty
LOW = a byte in THR
HIGH = transmitter empty
LOW = no data
HIGH = 1 byte
C
RYSTAL
T
(FIFO D
(FIFO D
FCR B
ABLE
FCR B
T
ABLE
C
ONNECTIONS
3: INTA
IT
ISABLED
IT
ISABLED
-0 = 0
-0 = 0
4: INTA
)
)
AND
AND
INTB P
22-47pF
XTAL1
INTB P
C1
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
LOW = FIFO below trigger level
HIGH = FIFO above trigger level
INS
500K - 1M
R2
IN
9
HIGH PERFORMANCE DUART WITH 16-BYTE FIFO
22-47pF
XTAL2
O
C2
Y1
O
PERATION FOR
PERATION
1.8432 MHz
(Optional)
24 MHz
0-120
R1
to
FCR B
F
OR
IT
(FIFO E
T
FCR B
-0 = 1 (FIFO E
RANSMITTER
R
Figure
ECEIVER
IT
NABLED
-0 = 1
4). The programmable Baud
NABLED
)
10.”
)
XR16V2550
Figures 17