AT89C5131A-L Atmel Corporation, AT89C5131A-L Datasheet - Page 116

• Manufacturer Part Number: AT89C5131A-L
• Manufacturer: Atmel Corporation

Specifications of AT89C5131A-L

• Flash (kbytes): 32 Kbytes
• Max. Operating Frequency: 48 MHz
• Cpu: 8051-12C
• Max I/o Pins: 34
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Sram (kbytes): 1.25
• Eeprom (bytes): 1024
• Self Program Memory: API
• Operating Voltage (vcc): 3.0 to 3.6
• Timers: 4
• Isp: UART/USB
• Watchdog: Yes

USB Controller
Description
Figure 56. USB Device Controller Block Diagram
116
AT89C5131A-L
D+
D-
USB
D+/D-
Buffer
DPLL
.
The USB device controller provides the hardware that the AT89C5131 needs to inter-
face a USB link to a data flow stored in a double port memory (DPRAM).
The USB controller requires a 48 MHz ±0.25% reference clock, which is the output of
the AT89C5131 PLL (see Section “PLL”, page 14) divided by a clock prescaler. This
clock is used to generate a 12 MHz Full-speed bit clock from the received USB differen-
tial data and to transmit data according to full speed USB device tolerance. Clock
recovery is done by a Digital Phase Locked Loop (DPLL) block, which is compliant with
the jitter specification of the USB bus.
The Serial Interface Engine (SIE) block performs NRZI encoding and decoding, bit stuff-
ing, CRC generation and checking, and the serial-parallel data conversion.
The Universal Function Interface (UFI) realizes the interface between the data flow and
the Dual Port RAM.
SIE
48 MHz
12 MHz
+/- 0.25%
UFI
C51
Microcontroller
Interface
Up to 48 MHz
UC_sysclk
4338F–USB–08/07