AT89C5122D-PSTUM Atmel, AT89C5122D-PSTUM Datasheet - Page 129

• Manufacturer Part Number: AT89C5122D-PSTUM
• Description: IC 8051 MCU FLASH 32K 64QFN
• Manufacturer: Atmel
• Series: 89Cr

Specifications of AT89C5122D-PSTUM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 48MHz
• Connectivity: SmartCard, SPI, UART/USART, USB
• Peripherals: LED, POR, WDT
• Number Of I /o: 46
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-QFN
• For Use With: AT89STK-10 - KIT EVAL APPL MASS STORAGEAT89STK-03 - KIT STARTER FOR MCU AT8XC5122/23
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -

Baud Rate Selection (Mode 0)
Asynchronous Modes
(Modes 1, 2 and 3)
Mode 1
4202F–SCR–07/2008
CLOCK
CLOCK
IBRG
CK_
T1
SI
In mode 0, baud rate can be either fixed or variable.
As shown in Figure 72, the selection is done using M0SRC bit in BDRCON register.
Figure 73 gives the baud rate calculation formulas for each baud rate source.
Figure 72. Baud Rate Source Selection (Mode 0)
Figure 73. Baud Rate Formulas (Mode 0)
The Serial Port has one 8-bit and two 9-bit asynchronous modes of operation. Figure 74
shows the Serial Port block diagram in such asynchronous modes.
Figure 74. Serial I/O Port Block Diagram (Modes 1, 2 and 3)
Mode 1 is a full-duplex, asynchronous mode. The data frame (see Figure 75) consists of
10 bits: one start, eight data bits and one stop bit. Serial data is transmitted on the TXD
pin and received on the RXD pin. When a data is received, the stop bit is read in the
RB8 bit in SCON register.
Baud_Rate =
CLOCK
IBRG
a. Fixed Formula
CK_
SI
SCON.4
SM2
SCON.6
M3 M2 M1 M0
SM1
Mode Decoder
Mode & Clock
F
CK_SI
Controller
/ 6
6
SCON.1
TI
SCON.7
SM0
BDRCON.0
M0SRC
SCON.0
RI
0
1
AT83R5122, AT8xC5122/23
To Serial Port
Baud_Rate =
BRL = 256 -
SCON.3
SBUF Tx SR
TB8
SBUF Rx
b. Variable Formula
Rx SR
6
6
(1-SPD)
(1-SPD)
2
2
SMOD1
SMOD1
32 (256 -BRL)
32 Baud_Rate
SCON.2
RB8
F
F
CK_SI
CK_SI
TXD
RXD
129