em78p5842 ELAN Microelectronics Corp, em78p5842 Datasheet - Page 14

• Manufacturer Part Number: em78p5842
• Description: 8-bit Micro-controller
• Manufacturer: ELAN Microelectronics Corp

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* This specification is subject to change without notice.
R9 (PORT9 I/O data)
PAGE0 (PORT9 I/O data register)
PAGE1: (undefined) not allowed to use
PAGE2: (undefined) not allowed to us
PAGE3 (DT2L: the Least Significant Byte ( Bit 7 ~ Bit 0 ) of Duty Cycle of PWM2)
RA (PLL, Main clock selection, Watchdog timer)
PAGE0 (PLL enable bit, Main clock selection bits, Watchdog timer enable bit)
PWM2[7] PWM2[6] PWM2[5] PWM2[4] PWM2[3] PWM2[2] PWM2[1] PWM2[0]
R/W-0
R/W-0
R/W
P97
Bit 0 ~ Bit 7 (P90 ~ P97) : 8-bit PORT9(0~7) I/O data register
Bit 0(WDTEN) : Watch dog control bit.
0/1 Î disable/enable
User can use WDTC instruction to clear watch dog counter. The watchdog timer is a free running on-chip RC
oscillator. The WDT will keep on running even after the oscillator driver has been turned off (i.e. in sleep mode).
During normal operation or sleep mode, a WDT time-out (if enabled) will cause the device to reset. The WDT can
be enabled or disabled at any time during the green mode or normal mode by software programming. Without
presacler, the WDT time-out period is approximately 18 ms.
Bit 1~Bit 2 : Unused
Bit 3 ~ Bit 5 (CLK0 ~ CLK2) : MAIN clock selection bits on Crystal mode. These three bits are unused on
IRC and ERIC mode.
In Crystal mode:
Bit 6(PLLEN) : PLL's power control bit which is CPU mode control register. This bit is only used in crystal
7
User can use IOC register to define input or output each bit.
7
A specified value keeps the output of PWM2 to stay at high until the value matches with TMR2.
7
0
User can choose different frequency of main clock by CLK1 and CLK2. All the clock selection is list below.
0/1 Î disable PLL/enable PLL
PLLEN
1
1
1
1
1
1
1
1
0
PLLEN
R/W-0
R/W-0
mode. In RC mode, this bit will be ignored.
R/W
P96
6
6
6
don’t care don’t care don’t care 32.768kHz
CLK2
0
0
0
0
1
1
1
1
R/W-0
R/W-0
CLK2
R/W
P95
5
5
5
CLK1
0
0
1
1
0
0
1
1
R/W-0
R/W-0
CLK1
R/W
P94
4
4
4
CLK0
0
1
0
1
0
1
0
1
R/W-0
R/W-0
CLK0
R/W
P93
3
3
3
Sub clock
32.768kHz
32.768kHz
32.768kHz
32.768kHz
32.768kHz
32.768kHz
32.768kHz
32.768kHz
12
R/W-0
R/W
P92
2
2
X
-
2
MAIN clock
3.582MHz
3.582MHz
3.582MHz
3.582MHz
14.3MHz
14.3MHz
14.3MHz
14.3MHz
don’t care
R/W-0
R/W
P91
1
1
X
-
1
R/W-0
14.3MHz (Normal mode)
CPU clock
3.582MHz (Normal mode)
3.582MHz (Normal mode)
3.582MHz (Normal mode)
3.582MHz (Normal mode)
14.3MHz (Normal mode)
14.3MHz (Normal mode)
14.3MHz (Normal mode)
32.768kHz (Green mode)
R/W
P90
WDTEN
0
0
R/W-0
EM785840/5841/5842
8-bit Micro-controller
0
2004/11/10 V1.2