EM78P5840/5841/5842
8-bit Micro-controller
IOCB (ADC control)
PAGE0 (Unused)
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
** This page must clear to 0 or MCU power consumption will increase.
The default value in these 8 bits are “1”. Please clear them to “0” when init MCU.
PAGE1 (ADC control bits)
7
6
5
4
3
2
1
0
0
IN2
IN1
IN0
ADCLK1 ADCLK0 ADPWR
ADST
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0 R/W-0 R/W-0
Bit 0(ADST) : AD converter start to sample
By setting to “1”, the AD will start to sample data. This bit will be cleared by hardware automatically after a
sampling.
Bit 1 : (undefined) not allowed to use. This bit must clear to 0.
Bit 2(ADPWR) : AD converter power control, 1/0 Î enable/disable.
Bit 3 ~ Bit 4 (ADCLK0 ~ ADCLK1) : AD circuit ‘s sampling clock source.
For Crystal mode:
ADCLK1 ADCLK0
Sampling rate
74.6K
Operation voltage
>=3.5V
0
0
1
1
0
1
0
1
37.4K
>=3.0V
18.7K
>=2.5V
9.3K
>=2.5V
For IRC or ERIC mode, AD converter rate will change by oscillator. The formula for input frequency and AD
converter rate is: AD converter rate = oscillator / 4 / (2^ADCLK)/12
For example, if input CLK = 4M Hz:
ADCLK1 ADCLK0
Sampling rate
83.3K
Operation voltage
>=3.5V
0
0
1
1
0
1
0
1
41.7K
>=3.0V
20.8K
>=2.5V
10.4K
>=2.5V
* Please avoid AD converter rate over 50K Hz, it maybe decrease ADC’s resolution.
This is a CMOS multi-channel 10-bit successive approximation A/D converter.
Features
74.6kHz maximum conversion speed (Crystal mode) at 5V.
Adjusted full scale input
Internal (VDD) reference voltage
8 analog inputs multiplexed into one A/D converter
Power down mode for power saving
A/D conversion complete interrupt
Interrupt register, A/D control and status register, and A/D data register
__________________________________________________________________________________________________________________________________________________________________
* This specification is subject to change without notice.
21
2004/11/10 V2.6
ELAN [ ELAN MICROELECTRONICS CORP ]
