EM78P5840/5841/5842

8-bit Micro-controller

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* This specification is subject to change without notice.

30

2004/11/10

V2.6

VII.9_1 Code Option

EM78P5840 CODE Option Register

12

11

10

9

8

7

6

5

4

3

2

1

0

IR3 IR2 IR1 IR0 P71S P70S OSCM1 OSCM0

IRC2S

MER

1

1

/POT0

Bit 0 (/POT0): program ROM protect option.

If set 1 to the bit, program memory can be access; else if clear this bit , program memory can not be

access.

Bit 3(MER) : Memory error recover function

0

disable memory error recover function

1

enable memory error recovery function

If user enable memory error recovery function, MCU will improve effect from environment noise.

Bit 4 (IRC2S): Internal RC oscillating frequency (for system CLK) select.

0

2M Hz

1

4M Hz

Bit5~Bit6 (OSCM0~OSCM1): EM78P5840 oscillating mode select.

OSCM1

OSCM0

Oscillating mode

0

0

IRC mode

0

1

ERIC mode

1

X

Crystal mode

Bit 7 (P70S): PORT70 function select bit:

OSCM1

OSCM0

P70S

PORT70 status

0

0

X

General Purpose IO

0

1

X

OSC input, please cascade resister to AVDD

1

X

1

PLLC output, please cascade capacitor to AVSS

1

X

0

General Purpose IO, PLL function will disable

Bit 8 (P71S): PORT71 function select bit:

0

/RESET pin selected..

1

General purpose INPUT port “PORT71” selected

Bit 9~ Bit12 (IR0~IR3): By setting IR0~IR3, IRC mode’s oscillating frequency can be adjust. Next table

show the trimming code table of IRC frequency.

IR3~IR0

Frequency

0000

1.05*F

0001

1.10*F

0010

1.15*F

0011

1.20*F

0100

1.25*F

0101

1.30*F

0110

1.35*F

0111

1.40*F

1000

0.65*F

1001

0.70*F

1010

0.75*F

1011

0.80*F

1100

0.85*F

1101

0.90*F

1110

0.95*F

1111

1.0*F

* ”F” means the frequency of IRC output.