em78p468l ELAN Microelectronics Corp, em78p468l Datasheet - Page 52

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

EM78P468N/EM78P468L
8-Bit Microcontroller
46 •
6.12
Bit 3 (HLP): Power consumption selection. If the system usually runs in green mode, it
must be set to low power consumption to help support the energy saving issue. It is
recommended that low power consumption mode is selected.
Bits 2~0 (PR2~PR0): Protect Bit
PR2~PR0 are protection bits. Each protect status is as follows:
Instruction Set
Each instruction in the instruction set is a 13-bit word divided into an OP code and one
or more operands. Normally, all instructions are executed within one single instruction
cycle (one instruction consists of 2 oscillator periods), unless the program counter is
changed by instruction "MOV R2,A", "ADD R2,A", or by instructions of arithmetic or
logic operation on R2 (e.g. "SUB R2,A", "BS(C) R2,6", "CLR R2", ⋅⋅⋅⋅ ). In this case, the
execution takes two instruction cycles.
If for some reasons, the specification of the instruction cycle is not suitable for certain
applications, try modifying the instruction as follows :
Execute within two instruction cycles the "JMP", "CALL", "RET", "RETL", & "RETI"
instructions, or the conditional skip instructions ("JBS", "JBC", "JZ", "JZA", "DJZ",
"DJZA") which were tested to be true. Also execute within two instruction cycles the
instructions that are written to the program counter.
Additionally, the instruction set offers the following features :
(1) Every bit of any register can be set, cleared, or tested directly.
(2) The I/O register can be regarded as general register. That is, the same instruction
can operate on I/O register.
PR2
0
1
HLP = “0”: Low power consumption mode
HLP = “1”: High power consumption mode
PR1
0
1
(This specification is subject to change without further notice)
PR0
0
1
Product Specification (V1.5) 02.15.2007
Protect
Disable
Enable