ADE5166_08 AD [Analog Devices], ADE5166_08 Datasheet - Page 97

• Manufacturer Part Number: ADE5166_08
• Description: Single-Phase Energy Measurement IC with 8052 MCU, RTC, and LCD Driver
• Manufacturer: AD [Analog Devices]

Table 101. LCD Data Memory Accessed Indirectly Through LCD Pointer SFR (LCDPTR, Address 0xAC) and LCD Data SFR (LCDDAT,
Address 0xAE)
LCD Memory Address
0x0E
0x0D
0x0C
0x0B
0x0A
0x09
0x08
0x07
0x06
0x05
0x04
0x03
0x02
0x01
0x00
1
2
VOLTAGE GENERATION
The ADE5166/ADE5169 provide two ways to generate the LCD
waveform voltage levels. The on-chip charge pump option can
generate 5 V. This makes it possible to use 5 V LCDs with the 3.3 V
ADE5166/ADE5169. There is also an option to use an external
resistor ladder with a 3.3 V LCD. The EXTRES bit (Bit 6) in the
LCD Configuration X SFR (LCDCONX, Address 0x9C) selects
the resistor ladder or charge pump option.
When selecting how to generate the LCD waveform voltages,
the following should be considered:
•
•
Lifetime Performance Power Consumption
In most LCDs, a high amount of current is required when the LCD
waveforms change state. The external resistor ladder option draws a
constant amount of current, whereas the charge pump circuitry
allows dynamic current consumption. If the LCD module is used
with the internal charge pump option when the display is disabled,
the voltage generation is disabled so that no power is consumed by
the LCD function. This feature results in significant power
savings if the display is turned off during battery operation.
Contrast Control
The electrical characteristics of the liquid in the LCD change
over temperature. This requires adjustments in the LCD waveform
voltages to ensure a readable display. An added benefit of the
COMx designates the common lines.
FPx designates the segment lines.
Lifetime performance power consumption
Contrast control
1, 2
COM3
FP27
FP25
FP23
FP21
FP19
FP17
FP15
FP13
FP11
FP9
FP7
FP5
FP3
FP1
LCD Pointer SFR (LCDPTR, Address 0xAC)
COM2
FP27
FP25
FP23
FP21
FP19
FP17
FP15
FP13
FP11
FP9
FP7
FP5
FP3
FP1
COM1
FP27
FP25
FP23
FP21
FP19
FP17
FP15
FP13
FP11
FP9
FP7
FP5
FP3
FP1
Rev. 0 | Page 97 of 148
COM0
FP27
FP25
FP23
FP21
FP19
FP17
FP15
FP13
FP11
FP9
FP7
FP5
FP3
FP1
internal charge pump voltage generation is a configurable bias
voltage that can be compensated over temperature and supply
to maintain contrast on the LCD. These compensations can be
performed based on the ADE5166/ADE5169 temperature and
supply voltage measurements (see the Temperature, Battery, and
Supply Voltage Measurements section). This dynamic contrast
control is not easily implemented with external resistor ladder
voltage generation.
The LCD bias voltage sets the contrast of the display when the
charge pump provides the LCD waveform voltages. The ADE5166/
ADE5169 provide 64 bias levels selected by the BIASLVL[5:0]
bits in the LCD Configuration X SFR (LCDCONX, Address 0x9C).
The voltage level on LCDVA, LCDVB, and LCDVC depend on the
internal voltage reference value (V
tion, and the biasing selected, as described in Table 92.
Lifetime Performance
DC offset on a segment degrades its performance over time.
The voltages generated through the internal charge pump
switch faster than those generated by the external resistor
ladder, reducing the likelihood of a dc voltage being applied
to a segment and increasing the lifetime of the LCD.
LCD EXTERNAL CIRCUITRY
The voltage generation selection is made by the EXTRES bit
(Bit 6) in the LCD configuration X SFR (LCDCONX,
Address 0x9C). This bit is cleared by default for charge pump
voltage generation, but it can be set to enable an external
resistor ladder.
COM3
FP28
N/A
FP24
FP22
FP20
FP18
FP16
FP14
FP12
FP10
FP8
FP6
FP4
FP2
FP0
LCD Pointer SFR (LCDDAT, Address 0xAE)
COM2
FP28
N/A
FP24
FP22
FP20
FP18
FP16
FP14
FP12
FP10
FP8
FP6
FP4
FP2
FP0
REF
ADE5166/ADE5169
), BIASLVL (Bits[5:0]) selec-
COM1
FP28
N/A
FP24
FP22
FP20
FP18
FP16
FP14
FP12
FP10
FP8
FP6
FP4
FP2
FP0
COM0
FP28
N/A
FP24
FP22
FP20
FP18
FP16
FP14
FP12
FP10
FP8
FP6
FP4
FP2
FP0