Code Option Register - Elan EM78P156EL Manual

100 pF
300 pF
<Note> 1. Measured on DIP packages.
2. For design reference only.

4.8 CODE Option Register

The EM78P156EL has a CODE option word that is not a part of the normal program memory. The
option bits cannot be accessed during normal program execution.
Code Option Register and Customer ID Register arrangement distribution:
Word 0
Bit12~Bit0
1. Code Option Register (Word 0)
Bit12
MS /ENWDT
• Bit 12 (MS):Oscillator type selection.
0: RC type
1: XTAL type (XTAL1 and XTAL2)
• Bit 11 (/ENWDT): Watchdog timer enable bit.
0: Enable
1: Disable
• Bit 10 (CLK): Instruction period option bit.
0: two oscillator periods.
1: four oscillator periods.
Refer to the section on Instruction Set.
• Bit 9 (CS): Code Security Bit
0: Security On
1: Security Off
• Bit 8 (HLF): XTAL frequency selection
0: XTAL2 type (low frequency, 32.768KHz)
This specification is subject to change without prior notice.
3.3k
5.1k
10k
100k
3.3k
5.1k
10k
100k
Word 1
Bit12~Bit0
Bit11 Bit10 Bit9
CLK CS
1.39 MHz
940 KHz
480 KHz
52 KHz
595 KHz
400 KHz
200 KHz
21 KHz
WORD 0
Bit8 Bit7 Bit6 Bit5
HLF - HLP
29
EM78P156EL
1.33 MHz
920 KHz
475 KHz
50 KHz
560 KHz
390 KHz
200 KHz
20 KHz
Bit4 Bit3 Bit2
- - - -
OTP ROM
Bit1 Bit0
- -
2002/04/19