SX28AC75-ISLASHTQ datasheet(33/52 Pages) ETC

Part #	SX28AC75-I/TQ

Description	Configurable Communications Controllers with EE/Flash Program Memory, In-System Programming Capability and On-Chip Debug

PDF	52 Pages

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Manufacturer	ETC [List of Unclassifed Manufacturers]

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SX18AC/SX20AC/SX28AC/SX18AC75/SX20AC75/SX28AC75

15.12

Subroutine Operation

15.12.1 Push Operation

When a subroutine is called, the return address is

pushed onto the subroutine stack. Specifically, each

address in the stack is moved to the next lower level in

order to make room for the new address to be stored.

Stack 1 receives the contents of the program counter.

Stack 8 is overwritten with what was in Stack 7. The con-

tents of stack 8 are lost.

15.12.2 Pop Operation

When a return instruction is executed the subroutine

stack is popped. Specifically, the contents of Stack 1 are

copied into the program counter and the contents of each

stack level are moved to the next higher level. For exam-

ple, Stack 1 receives the contents of Stack 2, etc., until

Stack 7 is overwritten with the contents of Stack 8. Stack

8 is left unchanged, so the contents of Stack 8 are dupli-

cated in Stack 7.

PC<10:0>

STACK 1

STACK 2

STACK 3

STACK 4

STACK 5

STACK 6

STACK 7

STACK 8