EM78P5840N/41N/42N
8-Bit Microcontrollers
7.5 Code Option Register
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
IR3 IR2 IR1 IR0
P71S P70S OSCM1 OSCM0 IRC2S
0
1
1
/POT0
Bit 0 (/POT0): Program ROM protect option
If this bit is set to “1,” you can access the program memory; else if this
bit is “0,” you cannot access the program memory.
Bits 1~2:
Bit 3:
Not used (reserved). These bits are always set to “1”
Not used (reserved). This bit is always set to “0”
Bit 4 (IRC2S): Select internal RC oscillation frequency (for system CLK)
"0" : 2MHz
"1" : 4MHz
Bit 5 ~ Bit 6 (OSCM0 ~ OSCM1): Select Oscillation mode
OSCM1
OSCM0
Oscillation Mode
0
0
1
0
1
×
IRC mode
ERIC mode
Crystal mode
Bit 7 (P70S): Port 70 function select bit
OSCM1
OSCM0
P70S
Port 70 Status
General Purpose IO
0
0
×
OSC input, you must cascade resister
to AVDD
0
1
1
1
×
×
×
1
0
PLLC output, you must cascade
capacitor to AVSS
General Purpose IO, PLL function will
be disabled
Bit 8 (P71S): Port 71 function select bit
"0" : /RESET pin is selected
"1" : General purpose input port Port 71 is selected
Bit 9 ~ Bit 12 (IR0 ~ IR3): Internal RC mode Calibrator
IR0~3 must be set to “1” only (IRC frequency auto calibration).
32 •
Product Specification (V1.0) 04.25.2006
(This specification is subject to change without further notice)
ELAN [ ELAN MICROELECTRONICS CORP ]
