TOS

Contents of the stack pointed to by the STKPTR register. This is the value that will be loaded into the Program Counter upon a RETURN or RETFIE instruction.

Note: The individual bytes in this multi-byte register can be accessed with the following register names:

TOSU: Accesses the upper byte TOS[20:16]
TOSH: Accesses the high byte TOS[15:8]
TOSL: Accesses the low byte TOS[7:0]

Bit23	22	21	20	19	18	17	16
			TOS[20:16]
Access			R/W	R/W	R/W	R/W	R/W
Reset			0	0	0	0	0
Bit15	14	13	12	11	10	9	8
TOS[15:8]
AccessR/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset0	0	0	0	0	0	0	0
Bit7	6	5	4	3	2	1	0
TOS[7:0]
AccessR/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset0	0	0	0	0	0	0	0

Bits 20:0 – TOS[20:0]: Top-of-Stack