EKTF6708 datasheet(19/158 Pages) EMC

19 / 158 page

eKTF6708

8-Bit Microcontroller

IC Product Specification (V1.2) 03.12.2020

 9

(This specification is subject to change without prior notice)

6.1.3 R2: PCL (Program Counter Low)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

PC7

PC6

PC5

PC4

PC3

PC2

PC1

PC0

R/W

Bits 7~0 (PC7~PC0): The low byte of program counter.



Depending on the device type, R2 and hardware stack are 16-bits wide. The structure

is depicted in Figure 6-1 eKTF6708 Program Counter Organization.



Generating 6K

16 bits on-chip Flash ROM addresses to the relative programming

instruction codes. One program page is 4096 words long.



R2 is set as all "0"s when under RESET condition.



"JMP" instruction allows direct loading of the lower 12 program counter bits. Thus,

"JMP" allows PC to go to any location within a page.



"LJMP" instruction allows direct loading of the lower 13 program counter bits.

Therefore, "LJMP" allows PC to jump to any location within 6K (213).



"CALL" instruction loads the lower 12 bits of the PC, and the present PC value will add

1 and is pushed into the stack. Thus, the subroutine entry address can be located

anywhere within a page.



"LCALL" instruction loads the lower 13 bits of the PC, and then PC+1 is pushed into the

stack. Thus, the subroutine entry address can be located anywhere within 6K (213).



"RET" ("RETL k", "RETI") instruction loads the program counter with the contents of the

top-level stack.



"ADD R2, A" allows a relative address to be added to the current PC, and the ninth and

above bits of the PC will increase progressively.



"MOV R2, A" allows to load an address from the "A" register to the lower 8 bits of the

PC, and the ninth and above bits of the PC won’t be changed.



Any instruction except “ADD R2,A” that is written to R2 (e.g. "MOV R2, A", "BC R2,

6",“INC R2”,

) will cause the ninth bit and the above bits (PC8~PC12) of the PC not

change.



All instructions are single instruction cycle (Fsys/2) except

“LCALL”, ”CALL”, ”LJMP”and “JMP” instructions. The “LCALL” and “LJMP” instructions

need two instructions cycle.

EKTF6708 Datasheet(PDF) 19 Page - ELAN Microelectronics Corp

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