AT89C51SND2C-7FTUL Atmel, AT89C51SND2C-7FTUL Datasheet - Page 168

• Manufacturer Part Number: AT89C51SND2C-7FTUL
• Description: IC 8051 MCU FLASH 64K MP3 100BGA
• Manufacturer: Atmel
• Series: 89Cr

Specifications of AT89C51SND2C-7FTUL

• 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: 32
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: FLASH
• Ram Size: 2.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.3 V
• Data Converters: A/D 2x10b; D/A 2x20b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 100-TFBGA
• Data Bus Width: 8 bit
• Data Ram Size: 2.25 KB
• Interface Type: ATAPI, I2S, IDE, SPI, UART, USB
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 2
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details
• Other names: AT89C51SND2C7FTUL

20. Serial I/O Port
20.1
20.2
20.2.1
168
Mode Selection
Baud Rate Generator
AT8xC51SND2C/MP3B
Timer 1
The serial I/O port in the AT8xC51SND2C provides both synchronous and asynchronous com-
munication modes. It operates as a Synchronous Receiver and Transmitter in one single mode
(Mode 0) and operates as an Universal Asynchronous Receiver and Transmitter (UART) in three
full-duplex modes (Modes 1, 2 and 3). Asynchronous modes support framing error detection and
multiprocessor communication with automatic address recognition.
SM0 and SM1 bits in SCON register (see Figure 20-3) are used to select a mode among the sin-
gle synchronous and the three asynchronous modes according to
Table 20-1.
Depending on the mode and the source selection, the baud rate can be generated from either
the Timer 1 or the Internal Baud Rate Generator. The Timer 1 can be used in Modes 1 and 3
while the Internal Baud Rate Generator can be used in Modes 0, 1
and 3.
The addition of the Internal Baud Rate Generator allows freeing of the Timer 1 for other pur-
poses in the application. It is highly recommended to use the Internal Baud Rate Generator as it
allows higher and more accurate baud rates than Timer 1.
Baud rate formulas depend on the modes selected and are given in the following mode sections.
When using Timer 1, the Baud Rate is derived from the overflow of the timer. As shown in
Figure 20-1 Timer 1 is used in its 8-bit auto-reload mode (detailed in Section "Mode 2 (8-bit
Timer with Auto-Reload)", page 54). SMOD1 bit in PCON register allows doubling of the gener-
ated baud rate.
SM0
0
0
1
1
SM1
0
1
0
1
Serial I/O Port Mode Selection
Mode
0
1
2
3
Description
Synchronous Shift Register
8-bit UART
9-bit UART
9-bit UART
Baud Rate
Fixed/Variable
Variable
Fixed
Variable
Table
20-1.
4341H–MP3–10/07