EM78P259N/260N

8-Bit Microprocessor with OTP ROM

6.13Code Option

EM78P259N/260N has two Code option words and one Customer ID word that are not part of the normal program memory.

Word 0

 

Word1

 

Word 2

Bit12 ~ Bit0

 

Bit12 ~ Bit0

 

Bit12 ~ Bit0

 

 

 

 

 

6.13.1 Code Option Register (Word 0)

Word 0

Bit 12

Bit 11

Bit 10

Bit 9

Bit 8

Bit 7

Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

TYPE CLKS

ENWDTB

OSC2 OSC1 OSC0 HLP

PR2

PR1

PR0

Bits 12 ~ 10: Not used (reserved). These bits are set to “1” all the time

Bit 9 (TYPE): Type selection for EM78P259N or EM78P260N 0 = EM78P260N

1 = EM78P259N (default)

Bit 8 (CLKS): Instruction period option bit 0 = two oscillator periods

1 = four oscillator periods (default) Refer to Section 6.15 for Instruction Set

Bit 7 (ENWDTB): Watchdog timer enable bit 0 = Enable

1 = Disable (default)

Bits 6, 5 & 4 (OSC2, OSC1 & OSC0): Oscillator Mode Selection bits

 

 

Oscillator Modes

OSC2

OSC1

OSC0

 

 

 

 

 

ERC1

(External RC oscillator mode); P70/OSCO acts as P70

0

0

0

ERC1

(External RC oscillator mode); P70/OSCO acts as OSCO

0

0

1

IRC2

(Internal RC oscillator mode); P70/OSCO acts as P70

0

1

0

IRC2

(Internal RC oscillator mode); P70/OSCO acts as OSCO

0

1

1

LXT3 (Low Crystal oscillator mode)

1

1

0

HXT3 High Crystal oscillator mode) (default)

1

1

1

1In ERC mode, OSCI is used as oscillator pin. OSCO/P70 is defined by code option Word 0 Bit 6 ~ Bit 4.

2In IRC mode, P55 is normal I/O pin. OSCO/P70 is defined by code option Word 0 Bit 6 ~ Bit 4.

3In LXT and HXT modes; OSCI and OSCO are used as oscillator pins. These pins cannot and

should not be defined as normal I/O pins.

NOTE

The transient point of the system frequency between HXT and LXY is around 400kHz.

Product Specification (V1.2) 05.18.2007

• 67

(This specification is subject to change without further notice)

Page 73
Image 73
IBM EM78P259N/260N manual Code Option Register Word, Word Word1 Bit12 ~ Bit0