HT46R065D Просмотр технического описания (PDF) - Holtek Semiconductor

Номер в каталоге

Компоненты Описание

производитель

HT46R065D

Enhanced A/D Type MCU with High Current LED Driver

Holtek Semiconductor 

HT46R064D/065D/066D

Enhanced A/D Type 8-Bit OTP MCU with LED Driver

For instructions involving branches, such as jump or call instructions, two instruction cycles are

required to complete instruction execution. An extra cycle is required as the program takes one cycle to

first obtain the actual jump or call address and then another cycle to actually execute the branch. The

requirement for this extra cycle should be taken into account by programmers in timing sensitive

applications.

1

M O V A ,[1 2 H ]

2

C A LL D E LA Y

3

C P L [1 2 H ]

4

:

5

:

6 D E LA Y : N O P

F e tc h In s t. 1

E x e c u te In s t. 1

F e tc h In s t. 2

E x e c u te In s t. 2

F e tc h In s t. 3

F lu s h P ip e lin e

F e tc h In s t. 6

E x e c u te In s t. 6

F e tc h In s t. 7

Instruction Fetching

Program Counter

During program execution, the Program Counter is used to keep track of the address of the next

instruction to be executed. It is automatically incremented by one each time an instruction is executed

except for instructions, such as ²JMP² or ²CALL² that demand a jump to a non-consecutive Program

Memory address. Note that the Program Counter width varies with the Program Memory capacity

depending upon which device is selected. However, it must be noted that only the lower 8 bits, known

as the Program Counter Low Register, are directly addressable by user.

When executing instructions requiring jumps to non-consecutive addresses such as a jump instruction,

a subroutine call, interrupt or reset, etc., the microcontroller manages program control by loading the

required address into the Program Counter. For conditional skip instructions, once the condition has

been met, the next instruction, which has already been fetched during the present instruction

execution, is discarded and a dummy cycle takes its place while the correct instruction is obtained.

Device

HT46R064D

HT46R065D

HT46R066D

Program Counter

Program Counter High Byte PCL Register

PC9,PC8

PC10~PC8

PCL7~PCL0

PC11~PC8

The lower byte of the Program Counter, known as the Program Counter Low register or PCL, is

available for program control and is a readable and writeable register. By transferring data directly

into this register, a short program jump can be executed directly, however, as only this low byte is

available for manipulation, the jumps are limited to the present page of memory, that is 256 loca-

tions. When such program jumps are executed it should also be noted that a dummy cycle will be in-

serted.

The lower byte of the Program Counter is fully accessible under program control. Manipulating the

PCL might cause program branching, so an extra cycle is needed to pre-fetch. Further information on

the PCL register can be found in the Special Function Register section.

Rev. 1.00

14

January 12, 2011

Share Link: