AT80C51SND1C-ROTUL Atmel, AT80C51SND1C-ROTUL Datasheet - Page 137

• Manufacturer Part Number: AT80C51SND1C-ROTUL
• Description: IC MCU FLASH MP3 DECODER 80-TQFP
• Manufacturer: Atmel
• Series: 80Cr

Specifications of AT80C51SND1C-ROTUL

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, IDE/ATAPI, MMC, SPI, UART/USART, USB
• Peripherals: Audio, I²S, MP3, PCM, POR, WDT
• Number Of I /o: 44
• Program Memory Type: ROMless
• Ram Size: 2.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.3 V
• Data Converters: A/D 2x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 80-TQFP, 80-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Program Memory Size: -

18.3.3
18.4
18.4.0.1
4109L–8051–02/08
Asynchronous Modes (Modes 1, 2 and 3)
Baud Rate Selection (Mode 0)
Mode 1
In mode 0, the baud rate can be either, fixed or variable.
As shown in Figure 18-6, the selection is done using M0SRC bit in BDRCON register.
Figure 18-7 gives the baud rate calculation formulas for each baud rate source.
Figure 18-6. Baud Rate Source Selection (mode 0)
Figure 18-7. Baud Rate Formulas (Mode 0)
The Serial Port has one 8-bit and 2 9-bit asynchronous modes of operation. Figure 18-8 shows
the Serial Port block diagram in such asynchronous modes.
Figure 18-8. Serial I/O Port Block Diagram (Modes 1, 2 and 3)
Mode 1 is a full-duplex, asynchronous mode. The data frame (see Figure 18-9) 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.
CLOCK
CLOCK
CLOCK
IBRG
PER
T1
a. Fixed Formula
Baud_Rate
CLOCK
CLOCK
IBRG
PER
=
SCON.4
SM2
F
PER
6
SCON.6
M3 M2 M1 M0
SM1
Mode Decoder
Mode & Clock
Controller
SCON.1
TI
÷ 6
SCON.7
SM0
SCON.0
RI
BDRCON.0
M0SRC
0
1
BRL= 256
Baud_Rate=
To Serial Port
SBUF Tx SR
AT8xC51SND1C
SBUF Rx
b. Variable Formula
Rx SR
-
SCON.3
TB8
6
(1-SPD)
6
(1-SPD)
2
SMOD1
⋅
2
32
SMOD1
⋅
32
⋅
SCON.2
⋅
Baud_Rate
RB8
⋅
F
⋅
(256 -BRL)
PER
F
PER
TXD
RXD
137