EM78P458/459
OTP ROM
VDD
VDD
R1
R2
EM78P458
EM78P459
Q1
R3
/RESET
Fig.24 Circuit 2 for the Residue Voltage Protection
4.14 CODE OPTION
EM78P458/459 has one CODE option word and one Customer ID word that are not a part of the
normal program memory.
Word 0
Bit12~Bit0
Code option12~0
Word 1
Bit12~Bit0
Code option12~0
1. Code Option Register (Word 0)
Bit12
MS
Bit11
/ENWDT
Bit10
CLKS
Bit9
/PTB
Bit8
HLF
Bit7
RCT
Bit6
HLP
Bit5~Bit0
ID
• Bit 12 (MS): Oscillator type selection.
0: RC type
1: XTAL type
• Bit 11 (/ENWTD): Watchdog timer enable bit.
0: Enable
1: Disable
• Bit 10 (CLKS): Clocks of each instruction cycle.
0: Two clocks
1: Four clocks
Refer to the section of Instruction Set.
• Bit 9 (/PTB): Protect bit.
0: Enable
1: Disable
• Bit 8 (HLF): XTAL frequency selection.
0: Low frequency
This specification is subject to change without prior notice.
50
06.25.2004 (V1.4)
ELAN [ ELAN MICROELECTRONICS CORP ]
