ADE7518ASTZF16-RL Analog Devices Inc, ADE7518ASTZF16-RL Datasheet - Page 86

• Manufacturer Part Number: ADE7518ASTZF16-RL
• Description: 1-Phase Energy Meter IC
• Manufacturer: Analog Devices Inc

Specifications of ADE7518ASTZF16-RL

• Applications: Energy Measurement
• Core Processor: 8052
• Program Memory Type: FLASH (16 kB)
• Controller Series: ADE75xx
• Ram Size: 512 x 8
• Interface: I²C, SPI, UART
• Number Of I /o: 20
• Voltage - Supply: 3.135 V ~ 3.465 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 64-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ADE7518
LCD EXTERNAL CIRCUITRY
The voltage generation selection is made by setting Bit EXTRES
in the LCD Configuration X SFR (LCDCONX, 0x9C). This bit
is cleared by default and needs to be set to enable an external
resistor ladder.
External Resistor Ladder
To enable the external resistor ladder, set the EXTRES bit in
the LCD Configuration X SFR (LCDCONX, 0x9C). When
EXTRES = 1, the LCD waveform voltages are supplied by the
external resistor ladder. Because the LCD voltages are not
generated on chip, the LCD bias compensation implemented to
maintain contrast over temperature and supply is not possible.
The external circuitry needed for the resistor ladder option is
shown in Figure 77. The resistors required should be in the
range of 10 kΩ to 100 kΩ and based on the current required
by the LCD being used.
LCD FUNCTION IN PSM2
The LCDPSM2 and LCDEN bits in the LCD Configuration SFR
(LCDCON, 0x95) control LCD functionality in PSM2 operating
mode (see Table 79).
Table 79. Bits Controlling LCD Functionality in PSM2 Mode
LCDPSM2
0
0
1
In addition, note that the LCD configuration and data memory
is retained when the display is turned off.
Figure 76. External Circuitry for External Resistor Ladder Option 1/2 Bias
Figure 77. External Circuitry for External Resistor Ladder Option1/3 Bias
LCD WAVEFORM
LCD WAVEFORM
LCDEN
0
1
X
CIRCUITRY
CIRCUITRY
Configuration
Configuration
Result
The display is off in PSM2.
The display is on in PSM2.
The display is off in PSM2.
LCDVP1
LCDVP2
LCDVP1
LCDVP2
LCDVC
LCDVB
LCDVA
LCDVC
LCDVB
LCDVA
Rev. 0 | Page 86 of 128
Example LCD Setup
An example of how to set up the LCD peripheral for a specific
LCD is described in this section with the following parameters:
•
•
A 96-segment LCD with 4× multiplexing requires 96/4 = 24
segment lines. Sixteen pins, FP0 to FP15, are automatically
dedicated for use as LCD segments. Eight more pins must be
chosen for the LCD function. Because the LCD has 4× multi-
plexing, all four common lines are used. As a result, COM2/FP28
and COM3/FP27 cannot be used as segment lines. Based on the
alternate functions of the pins used for FP16 through FP25,
FP16 to FP23 are chosen for the eight remaining segment lines.
These pins are enabled for LCD functionality in the LCD
Segment Enable SFR (LCDSEGE, 0x97) and LCD Segment
Enable 2 SFR (LCDSEGE2, 0xED).
The LCD is set up with the following 8052 code:
; setup LCD pins to have LCD functionality
MOV
MOV
; set up LCDCON for f
bias and 4× multiplexing
MOV
; set up LCDCONX for resistor ladder
MOV
; set up refresh rate for 64 Hz with f
2048 Hz
MOV
; set up LCD data registers with data to be
displayed using
; LCDPTR and LCDDATA registers
; turn all segments on FP27 on and FP26 off
ORL
refresh
MOV
MOV
ANL
refresh
ORL
To set up the same 3.3 V LCD for use with an external resistor
ladder,
; set up LCDCONX for external resistor
ladder
MOV
Type of LCD: 4× multiplexed with 1/3 bias, 96 segments
Refresh rate: 64 Hz
LCDSEG,#FP20EN+FP21EN+FP22EN+FP23EN
LCDSEGX,#FP16EN+FP17EN+FP18EN+FP19EN
LCDCON,#BIAS+LMUX1+LMUX0
LCDCONX,#40h
LCDCLK,#FD3+FD2+FD1+FD0
LCDCONY,#01h ; start data memory
LCDDAT,#F0H
LCDCONY,#0FEh ; end of data memory
LCDCON,#LCDEN ; enable LCD
LCDCONX,#EXTRES
LCDPTR, #80h OR 0DH
LCDCLK
= 2048 Hz, 1/3
LCDCLK
=