EVAL-ADUC814QS Analog Devices Inc, EVAL-ADUC814QS Datasheet - Page 53

• Manufacturer Part Number: EVAL-ADUC814QS
• Description: KIT DEV FOR ADUC814 QUICK START
• Manufacturer: Analog Devices Inc
• Series: QuickStart™ Kitr
• Type: 8052-corer

Specifications of EVAL-ADUC814QS

• Contents: Evaluation Board, Power Supply, Cable, Software and Documentation
• For Use With/related Products: ADuC814
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

UART SERIAL INTERFACE
The serial port is full duplex, meaning it can transmit and
receive simultaneously. It is also receive-buffered, meaning it
can begin receiving a second byte before a previously received
byte has been read from the receive register. However, if the first
byte still has not been read by the time reception of the second
byte is complete, the first byte is lost. The physical interface to
the serial data network is via Pins RxD (P3.0) and TxD (P3.1),
while the SFR interface to the UART is comprised of the
following registers.
Table 26. SCON SFR Bit Designations
Bit No.
7
6
5
4
3
2
1
0
SM0
Name
SM0
SM1
SM2
REN
TB8
RB8
TI
RI
Description
UART Serial Mode Select Bits.
These bits select the serial port operating mode as follows:
SM0
Multiprocessor Communication Enable Bit.
Enables multiprocessor communication in Modes 2 and 3.
In Mode 0, SM2 should be cleared.
In Mode 1, if SM2 is set, RI is not activated if a valid stop bit is not received. If SM2 is cleared, RI is set as soon as the byte
of data is received.
In Mode 2 or 3, if SM2 is set, RI is not activated if the received ninth data bit in RB8 is 0. If SM2 is cleared, RI is set as soon
as the byte of data is received.
Serial Port Receive Enable Bit.
Set by the user software to enable serial port reception.
Cleared by the user software to disable serial port reception.
Serial Port Transmit (Bit 9).
The data loaded into TB8 is the ninth data bit that is transmitted in Modes 2 and 3.
Serial port Receiver Bit 9.
The ninth data bit received in Modes 2 and 3 is latched into RB8. For Mode 1, the stop bit is latched into RB8.
Set by hardware at the end of the eighth bit in Mode 0, or at the beginning of the stop bit in Modes 1, 2, and 3.
Cleared by the user software.
Serial Port Receive Interrupt Flag.
Set by hardware at the end of the eighth bit in Mode 0, or halfway through the stop bit in Modes 1, 2, and 3.
Cleared by user software.
0
0
1
1
SM1
SM1
0
1
0
1
Selected Operating Mode
Mode 0: Shift Register, fixed baud rate (Core_Clk/2)
Mode 1: 8-bit UART, variable baud rate
Mode 2: 9-bit UART, fixed baud rate (Core_Clk/64) or (Core_Clk/32)
Mode 3: 9-bit UART, variable baud rate
SM2
REN
Rev. A | Page 53 of 72
SBUF
The serial port receive and transmit registers are both accessed
through the SBUF SFR (SFR address = 99H). Writing to SBUF
loads the transmit register and reading SBUF accesses a
physically separate receive register.
SCON
SFR Address
Power-On Default
Bit Addressable
TB8
RB8
UART Serial Port Control Register
98H
00H
Yes
TI
ADuC814
RI