AT89C51SND2C-7FTUL Atmel, AT89C51SND2C-7FTUL Datasheet - Page 175

• 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

20.5
20.6
20.6.1
4341H–MP3–10/07
Multiprocessor Communication (Modes 2 and 3)
Automatic Address Recognition
Given Address
Figure 20-15. Baud Rate Formula (Mode 2)
Modes 2 and 3 provide a ninth-bit mode to facilitate multiprocessor communication. To enable
this feature, set SM2 bit in SCON register. When the multiprocessor communication feature is
enabled, the serial Port can differentiate between data frames (ninth bit clear) and address
frames (ninth bit set). This allows the AT8xC51SND2C to function as a slave processor in an
environment where multiple slave processors share a single serial line.
When the multiprocessor communication feature is enabled, the receiver ignores frames with
the ninth bit clear. The receiver examines frames with the ninth bit set for an address match. If
the received address matches the slaves address, the receiver hardware sets RB8 and RI bits in
SCON register, generating an interrupt.
The addressed slave’s software then clears SM2 bit in SCON register and prepares to receive
the data Bytes. The other slaves are unaffected by these data Bytes because they are waiting to
respond to their own addresses.
The automatic address recognition feature is enabled when the multiprocessor communication
feature is enabled (SM2 bit in SCON register is set).
Implemented in hardware, automatic address recognition enhances the multiprocessor commu-
nication feature by allowing the Serial Port to examine the address of each incoming command
frame. Only when the Serial Port recognizes its own address, the receiver sets RI bit in SCON
register to generate an interrupt. This ensures that the CPU is not interrupted by command
frames addressed to other devices.
If desired, the automatic address recognition feature in mode 1 may be enabled. In this configu-
ration, the stop bit takes the place of the ninth data bit. Bit RI is set only when the received
command frame address matches the device’s address and is terminated by a valid stop bit.
To support automatic address recognition, a device is identified by a given address and a broad-
cast address.
Note:
Each device has an individual address that is specified in SADDR register; the SADEN register
is a mask Byte that contains don’t care bits (defined by zeros) to form the device’s given
address. The don’t care bits provide the flexibility to address one or more slaves at a time. The
following example illustrates how a given address is formed.
To address a device by its individual address, the SADEN mask Byte must be 1111 1111b.
For example:
The following is an example of how to use given addresses to address different slaves:
Slave A:SADDR = 1111 0001b
SADDR = 0101 0110b
SADEN = 1111 1100b
Given = 0101 01XXb
The multiprocessor communication and automatic address recognition features cannot be
enabled in mode 0 (i.e, setting SM2 bit in SCON register in mode 0 has no effect).
Baud_Rate=
2
SMOD1
32
AT8xC51SND2C/MP3B
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