AT80C51SND1C-ROTUL Atmel, AT80C51SND1C-ROTUL Datasheet - Page 136

• 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: -

18.3.1
18.3.2
136
AT8xC51SND1C
Transmission (Mode 0)
Reception (Mode 0)
Figure 18-3. Serial I/O Port Block Diagram (Mode 0)
To start a transmission mode 0, write to SCON register clearing bits SM0, SM1.
As shown in Figure 18-4, writing the Byte to transmit to SBUF register starts the transmission.
Hardware shifts the LSB (D0) onto the RXD pin during the first clock cycle composed of a high
level then low level signal on TXD. During the eighth clock cycle the MSB (D7) is on the RXD
pin. Then, hardware drives the RXD pin high and asserts TI to indicate the end of the
transmission.
Figure 18-4. Transmission Waveforms (Mode 0)
To start a reception in mode 0, write to SCON register clearing SM0, SM1 and RI bits and setting
the REN bit.
As shown in Figure 18-5, Clock is pulsed and the LSB (D0) is sampled on the RXD pin. The D0
bit is then shifted into the shift register. After eight samplings, the MSB (D7) is shifted into the
shift register, and hardware asserts RI bit to indicate a completed reception. Software can then
read the received Byte from SBUF register.
Figure 18-5. Reception Waveforms (Mode 0)
Write to SCON
Write to SBUF
SCON.6
SCON.1
M3 M2 M1 M0
SM1
Mode Decoder
TI
Controller
RXD
RXD
TXD
TXD
Mode
RI
TI
SCON.7
SCON.0
SM0
RI
Set REN, Clear RI
D0
D0
D1
D1
CLOCK
CLOCK
BRG
PER
D2
D2
D3
D3
SBUF Rx SR
SBUF Tx SR
Baud Rate
Controller
D4
D4
D5
D5
D6
D6
D7
D7
4109L–8051–02/08
RXD
TXD