em78p468l ELAN Microelectronics Corp, em78p468l Datasheet - Page 14

• Manufacturer Part Number: em78p468l
• Description: 8-bit Microcontroller
• Manufacturer: ELAN Microelectronics Corp

EM78P468N/EM78P468L
8-Bit Microcontroller
8 •
6.1.4
Bit 7: Not used
Bits 6 ~ 5 (PS1 ~ 0): Page select bits
PS0~PS1 are used to select a ROM page. User can use the PAGE instruction (e.g.
PAGE 1) or set PS1~PS0 bits to change the ROM page. When executing a "JMP",
"CALL", or other instructions which causes the program counter to be changed (e.g.
MOV R2, A), PS0~PS1 are loaded into the 11th and 12th bits of the program counter
where it selects one of the available program memory pages. Note that RET (RETL,
RETI) instruction does not change the PS0~PS1 bits. That is, the return will always be
to the page from where the subroutine was called, regardless of the current setting of
PS0~PS1 bits.
Bit 4 (T): Time-out bit. Set to 1 by the "SLEP" and "WDTC" commands or during power
up and reset to 0 by WDT timeout.
Bit 3 (P): Power down bit. Set to 1 during power on or by a "WDTC" command and
Bit 2 (Z): Zero flag
Bit 1 (DC): Auxiliary carry flag
Bit 0 (C): Carry flag
WDT wake up from sleep mode
WDT time out (not sleep mode)
/RESET wake up from sleep
Power up
Low pulse on /RESET
Bit 7
PS1
−
(Address: 03h)
R3/SR (Status Register)
0
0
1
1
reset to 0 by a "SLEP" command.
Bit 6
PS1
Event
PS0
0
1
0
1
Bit 5
PS0
Bit 4
Page 3 (C00H ~ FFFH)
Page 2 (800H ~ BFFH)
Page 0 (000H ~ 3FFH)
Page 1 (400H ~ 7FFH)
ROM Page (Address)
(This specification is subject to change without further notice)
T
T
0
0
1
1
1
Bit 3
P
Product Specification (V1.5) 02.15.2007
P
0
1
0
1
1
Bit 2
Z
Bit 1
×: don't care
DC
Remark
Bit 0
C