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HT45R38 参数 Datasheet PDF下载

HT45R38图片预览
型号: HT45R38
PDF下载: 下载PDF文件 查看货源
内容描述: C / R键F型8位OTP MCU [C/R to F Type 8-Bit OTP MCU]
分类和应用:
文件页数/大小: 49 页 / 347 K
品牌: HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
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HT45R38  
Functional Description  
Execution Flow  
incremented by one. The program counter then points to  
the memory word containing the next instruction code.  
The system clock for the microcontroller is derived from  
either a crystal or an RC oscillator. The system clock is  
internally divided into four non-overlapping clocks. One  
instruction cycle consists of four system clock cycles.  
When executing a jump instruction, a conditional skip  
execution, loading the PCL register, a subroutine call,  
an initial reset, an internal interrupt, an external interrupt  
or return from a subroutine, the PC manipulates the pro-  
gram transfer by loading the address corresponding to  
each instruction.  
Instruction fetching and execution are pipelined in such  
a way that a fetch takes an instruction cycle while de-  
coding and execution takes the next instruction cycle.  
However, the pipelining scheme causes each instruc-  
tion to effectively execute in a cycle. If an instruction  
changes the program counter, two cycles are required to  
complete the instruction.  
The conditional skip is activated by instructions. Once  
the condition is met, the next instruction, fetched during  
the current instruction execution, is discarded and a  
dummy cycle replaces it to get the proper instruction.  
Otherwise the program will proceed with the next in-  
struction.  
Program Counter - PC  
The program counter (PC) controls the sequence in  
which the instructions stored in program ROM are exe-  
cuted and its contents specify full range of program  
memory.  
The lower byte of the program counter (PCL) is a read-  
able and writable register (06H). Moving data into the  
PCL performs a short jump. The destination must be  
within the current Program Memory Page.  
After accessing a program memory word to fetch an in-  
struction code, the contents of the program counter are  
When a control transfer takes place, an additional  
dummy cycle is required.  
T
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3
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Execution Flow  
Program Counter  
Mode  
*11 *10 *9  
*8  
0
0
0
0
0
0
0
*7  
0
0
0
0
0
0
0
*6  
0
0
0
0
0
0
0
*5  
0
0
0
0
0
0
0
*4  
0
0
0
0
1
1
1
*3  
0
0
1
1
0
0
1
*2  
0
1
0
1
0
1
0
*1  
0
0
0
0
0
0
0
*0  
0
0
0
0
0
0
0
Initial Reset  
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
External Interrupt 0  
External Interrupt 1  
Timer/Event Counter 0 Overflow  
External RC Oscillation Converter Interrupt  
Timer/Event Counter 1 Overflow  
A/D Converter Interrupt  
Skip  
Program Counter+2  
*8 @7 @6 @5 @4 @3 @2 @1 @0  
Loading PCL  
*11 *10 *9  
Jump, Call Branch  
#11 #10 #9 #8 #7 #6 #5 #4 #3 #2 #1 #0  
S11 S10 S9 S8 S7 S6 S5 S4 S3 S2 S1 S0  
Return from Subroutine  
Program Counter  
Note: *11~*0: Program Counter bits  
#11~#0: Instruction code bits  
S11~S0: Stack register bits  
@7~@0: PCL bits  
Rev. 1.00  
7
December 13, 2006