W77E468 Просмотр технического описания (PDF) - Winbond

Номер в каталоге

Компоненты Описание

производитель

W77E468

8 BIT MICROCONTROLLER

Winbond 

Preliminary W77E468

EIE.7-5:Reserved bits, will read high

EWDI: Enable Watchdog timer interrupt

EX5: External Interrupt 5 Enable.

EX4: External Interrupt 4 Enable.

EX3: External Interrupt 3 Enable.

EX2: External Interrupt 2 Enable.

B REGISTER

Bit:

7

6

5

4

3

2

1

0

B.7

B.6

B.5

B.4

B.3

B.2

B.1

B.0

Mnemonic: B

Address: F0h

B.7-0:The B register is the standard 8052 register that serves as a second accumulator.

EXTENDED INTERRUPT PRIORITY

Bit:

7

6

5

4

3

2

1

0

-

-

-

PWDI PX5 PX4 PX3 PX2

Mnemonic: EIP

Address: F8h

EIP.7-5:Reserved bits.

PWDI: Watchdog timer interrupt priority.

PX5: External Interrupt 5 Priority. 0 = Low priority, 1 = High priority.

PX4: External Interrupt 4 Priority. 0 = Low priority, 1 = High priority.

PX3: External Interrupt 3 Priority. 0 = Low priority, 1 = High priority.

PX2: External Interrupt 2 Priority. 0 = Low priority, 1 = High priority.

INSTRUCTION

The W77E468 executes all the instructions of the standard 8032 family. The operation of these

instructions, their effect on the flag bits and the status bits is exactly the same. However, timing of

these instructions is different. The reason for this is two fold. Firstly, in the W77E468, each machine

cycle consists of 4 clock periods, while in the standard 8032 it consists of 12 clock periods. Also, in

the W77E468 there is only one fetch per machine cycle i.e. 4 clocks per fetch, while in the standard

8032 there can be two fetches per machine cycle, which works out to 6 clocks per fetch.

The advantage the W77E468 has is that since there is only one fetch per machine cycle, the number

of machine cycles in most cases is equal to the number of operands that the instruction has. In case

of jumps and calls there will be an additional cycle that will be needed to calculate the new address.

But overall the W77E468 reduces the number of dummy fetches and wasted cycles, thereby

improving efficiency as compared to the standard 8032.

- 30 -

Share Link: