W77E516 查看數據表（PDF） - Winbond

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W77E516

8-BIT MICROCONTROLLER

Winbond 

Preliminary W77E516

Timed Access

Bit:

7

TA.7

6

TA.6

5

TA.5

4

TA.4

3

TA.3

2

TA.2

1

TA.1

0

TfA.0

Mnemonic: TA

Address: C7h

TA: The Timed Access register controls the access to protected bits. To access protected bits, the

user must first write AAH to the TA. This must be immediately followed by a write of 55H to TA.

Now a window is opened in the protected bits for three machine cycles, during which the user

can write to these bits.

Timer 2 Control

Bit:

7

6

5

4

3

2

1

0

TF2 EXF2 RCLK TCLK EXEN2 TR2 C / T2 CP / RL2

Mnemonic: T2CON

Address: C8h

TF2: Timer 2 overflow flag: This bit is set when Timer 2 overflows. It is also set when the count is

equal to the capture register in down count mode. It can be set only if RCLK and TCLK are

both 0. It is cleared only by software. Software can also set or clear this bit.

EXF2: Timer 2 External Flag: A negative transition on the T2EX pin (P1.1) or timer 2 overflow will

cause this flag to set based on the CP / RL2 , EXEN2 and DCEN bits. If set by a negative

transition, this flag must be cleared by software. Setting this bit in software or detection of a

negative transition on T2EX pin will force a timer interrupt if enabled.

RCLK: Receive Clock Flag: This bit determines the serial port 0 time-base when receiving data in

serial modes 1 or 3. If it is 0, then timer 1 overflow is used for baud rate generation,

otherwise timer 2 overflow is used. Setting this bit forces timer 2 in baud rate generator

mode.

TCLK: Transmit Clock Flag: This bit determines the serial port 0 time-base when transmitting data

in modes 1 and 3. If it is set to 0, the timer 1 overflow is used to generate the baud rate

clock otherwise timer 2 overflow is used. Setting this bit forces timer 2 in baud rate

generator mode.

EXEN2: Timer 2 External Enable. This bit enables the capture/reload function on the T2EX pin if

Timer 2 is not generating baud clocks for the serial port. If this bit is 0, then the T2EX pin

will be ignored, otherwise a negative transition detected on the T2EX pin will result in

capture or reload.

TR2: Timer 2 Run Control. This bit enables/disables the operation of timer 2. Clearing this bit will

halt the timer 2 and preserve the current count in TH2, TL2.

C / T2 : Counter/Timer Select. This bit determines whether timer 2 will function as a timer or a

counter. Independent of this bit, the timer will run at 2 clocks per tick when used in baud

rate generator mode. If it is set to 0, then timer 2 operates as a timer at a speed

depending on T2M bit (CKCON.5), otherwise it will count negative edges on T2 pin.

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