Datasheet

71M6511/71M6511H

Single-Phase Energy Meter IC

DATA SHEET

NOVEMBER 2010

A Maxim Integrated Products Brand

Dedicated Segment Pins Shared w/ DIO4-DIO11 Shared w/ DIO14-DIO17

SEG0 SEG1 … SEG19 SEG24 … SEG31 SEG34 … SEG37

COM0 P0 P4 … P76 P80 … P108 P112 … P124

COM1 P1 P5 … P77 P81 … P109 P113 ... P125

COM2 P2 P6 … P78 P82 … P110 P114 … P126

COM3 P3 P7 … P79 P83 … P111 P115 … P127

Table 56: Liquid Crystal Display Segment Table (Typical)

Note: P0, P1, … Represent the pixel/segment numbers on the LCD.

A charge pump suitable for driving VLCD is included on-chip. This circuit creates 5V from the 3.3V supply. A contrast DAC is

provided that permits the LCD full-scale voltage to be adjusted between VLCD and 70% of VLCD. The LCD_NUM register

defines the number of dual purpose pins used for LCD segment interface.

LCD Voltage Boost Circuitry

A voltage boost circuit may be used to generate 5V from the 3.3V supply to support low-power 5V devices, such as LCDs.

Figure 10 shows a block diagram of the voltage boost circuitry including the voltage regulators for V2P5 and V2P5NV. When

activated using the I/O RAM register LCD_BSTEN (0x2020[7]), the boost circuitry provides an AC voltage at the VDRV output

pin (see the Applications section for details).

GNDD

V3P3D

VBAT

VOLT

REG

0.1V

V2P5

VLCD

VDRV

VOLTAGE

BOOST

LCD_BSTEN

LCD_IBST

GNDD

V2P5

V3P3DV2P5NV

Figure 10: LCD Voltage Boost Circuitry

UART (UART0) and Optical Port (UART1)

The 71M6511/6511H includes an interface to implement an IR or optical port. The pin OPT_TX is designed to directly drive an

external LED for transmitting data on an optical link (low-active). The pin OPT_RX, also low-active, is designed to sense the

input from an external photo detector used as the receiver for the optical link. These two pins are connected to a dedicated

UART port. OPT_TX can be tristated if it is desired to multiplex another I/O pin to the OPT_TX output. The control bit for the

OPT_TX output is the I/O RAM register OPT_TXDIS (0x2008[5]).