scc2681 NXP Semiconductors, scc2681 Datasheet - Page 7

• Manufacturer Part Number: scc2681
• Description: Dual Asynchronous Receiver/transmitter Duart
• Manufacturer: NXP Semiconductors

8. Consecutive write operations to the same command register require at least three edges of the X1 clock between writes.
9. This parameter is not applicable to the 28-pin device.
10. Operation to 0 MHz is assured by design. However, operation at low frequencies is not tested and has not been characterized.
Philips Semiconductors
BLOCK DIAGRAM
2004 Apr 06
Dual asynchronous receiver/transmitter (DUART)
X1/CLK
RESET
INTRN
D0–D7
A0–A3
WRN
CEN
RDN
X2
4
8
OPERATION CONTROL
INTERRUPT CONTROL
R/W CONTROL
BUS BUFFER
GENERATOR
SELECTORS
BAUD RATE
COUNTER/
XTAL OSC
ADDRESS
DECODE
CLOCK
TIMING
TIMER
CTUR
CSRB
CTLR
CSRA
IMR
ACR
ISR
Figure 2. Block Diagram
7
SHIFT REGISTER
HOLDING REG (3)
SHIFT REGISTER
SELECT LOGIC
DETECTORS (4)
HOLDING REG
OUTPUT PORT
CHANNEL A
CHANNEL B
(AS ABOVE)
INPUT PORT
CHANGE OF
FUNCTION
TRANSMIT
TRANSMIT
RECEIVE
RECEIVE
MRA1, 2
STATE
OPCR
OPR
CRA
SRA
IPCR
ACR
7
8
SCC2681
SD00085
TxDA
RxDA
TxDB
RxDB
IP0-IP6
OP0-OP7
V
GND
Product data
CC