NT68P61A Datasheet, PDF (13/48 Pages) List of Unclassifed Manufacturers – 8-Bit Microcontroller for Monitor (24K OTP ROM Type)

NT68P61A
4. RAM: 256 X 8 bits
256 X 8-bit SRAM is used for data memory and stack. The RAM addressing range is from $0080 to $017F. From $0100 to
$017F is used as the EDID data buffer when activating DDC1/2B mode transmission. The contents of RAM are
undetermined at power-up and are not affected by system reset. Software programmers can allocate stack area in the
RAM by setting stack pointer register S. Because the 6502 default stack pointer is $01FF, programmers must set register
S to FFH when starting the program, so the stack area will map $01FF - $0180 to $00FF - $0080.
as;
LDX
#$FF
TXS
$0000
$0025
$0080
$00FF
$0100
$017F
$0180
System Registers
Unused
RAM
EDID
stack pointer
Unused
$BFFF
$A000
(24K Bytes)
OTP
ROM
$FFFC
$FFFD
$FFFE
$FFFF
RST-L
RST-H
IRQ-L
IRQ-H
RESET vector
IRQ vector
13