W77E468 Просмотр технического описания (PDF) - Winbond

Номер в каталоге

Компоненты Описание

производитель

W77E468

8 BIT MICROCONTROLLER

Winbond 

Preliminary W77E468

The W77E468 is an 8052 compatible device that gives the user the features of the original 8052

device, but with improved speed and power consumption characteristics. It has the same instruction

set as the 8051 family, with one addition: DEC DPTR (op-code A5H, the DPTR is decreased by 1).

While the original 8051 family was designed to operate at 12 clock periods per machine cycle, the

W77E468 operates at a much reduced clock rate of only 4 clock periods per machine cycle. This

naturally speeds up the execution of instructions. Consequently, the W77E468 can run at a higher

speed as compared to the original 8052, even if the same crystal is used. Since the W77E468 is a

fully static CMOS design, it can also be operated at a lower crystal clock, giving the same throughput

in terms of instruction execution, yet reducing the power consumption.

The 4 clocks per machine cycle feature in the W77E468 is responsible for a three-fold increase in

execution speed. The W77E468 has all the standard features of the 8052, and has a few extra

peripherals and features as well.

Seven I/O Ports:

The W77E468 has six 8-bit I/O ports and one 4-bit I/O port, giving a total of 52 lines. Port 0 to Port 3

can be used as a 8-bit general I/O port with bit-addressable. Port 4 and Port 5 are 8-bit general I/O

port without bit-addressable. Port 6 is a 4-bit general I/O port without bit-addressable. Port 1 to Port 5

have internal pull-up, Port 0 is open-drain.

Serial I/O:

The W77E468 has two enhanced serial ports that are functionally similar to the serial port of the

original 8052 family. However the serial ports on the W77E468 can operate in different modes in

order to obtain timing similarity as well. Note that the serial port 0 can use Timer 1 or 2 as baud rate

generator, but the serial port 1 can only use Timer 1 as baud rate generator. The serial ports have the

enhanced features of Automatic Address recognition and Frame Error detection.

Timers:

The W77E468 has three 16-bit timers that are functionally similar to the timers of the 8052 family.

When used as timers, they can be set to run at either 4 clocks or 12 clocks per count, thus providing

the user with the option of operating in a mode that emulates the timing of the original 8052. The

W77E468 has an additional feature, the watchdog timer. This timer is used as a System Monitor or as

a very long time period timer.

Interrupts:

The Interrupt structure in the W77E468 is slightly different from that of the standard 8052. Due to the

presence of additional features and peripherals, the number of interrupt sources and vectors has been

increased. The W77E468 provides 12 interrupt resources with two priority level, including six external

interrupt sources, timer interrupts, serial I/O interrupts and power-fail interrupt.

Publication Release Date: January 1999

-7-

Revision A1

Share Link: