w681308 Winbond Electronics Corp America, w681308 Datasheet - Page 28

• Manufacturer Part Number: w681308
• Description: Usb Audio Controller
• Manufacturer: Winbond Electronics Corp America

8.7
The MCU serial port is a full-duplex port, and the MCU provides additional features, such as Frame Error Detection and
Automatic Address Recognition. The serial port is capable of synchronous and asynchronous communication. In
synchronous mode, the MCU generates the clock and operates in half-duplex mode. In asynchronous mode, the serial port
can simultaneously transmit and receive data. The transmit register and the receive buffer are both addressed as SBUF, but
any write to SBUF writes to the transmit register while any read from SBUF reads from the receive buffer. The serial port can
operate in four modes: MOD 0, MOD 1, MOD 2 and MOD 3.
8.8
The W681308 internal OTP ROM is designed to store all application firmware.
The OTP programming is done by the injection of hot electrons which are generated by avalanche impact ionization in the bit
cell. User can enter JTAG mode to program 8k OTP ROM through JTAG interface pins and signal of PCMT pin will go high
simultaneously. The signal of pin PCMT can be used to control external hardware device to apply 6.75V or 3.3V to
programming voltage pin VPP. The cells are initialized by ultraviolet light through internal photoemission from the floating
gate.
You can write zero to bit 7 of OTP address 0x1fff to turn on the read protection feature.
SCON
8kB One-Time Programmable Logic Device
Enable OTP Read Protection
98H
Serial Port (UART)
OTP ROM
SM0/FE
Bit 7
SM1
Bit 6
Table 10 Serial Control SCON SFR
SM2
Bit 5
XXXX PRODUCT DESCRIPTION
Bit 4
REN
28
Bit 3
TB8
Bit 2
RB8
Bit 1
TI
W681308
Rev1.2
Bit 0
RI