PCF2119VU-2 Ver la hoja de datos (PDF) - Philips Electronics

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Fabricante

PCF2119VU-2

LCD controllers/drivers

Philips Electronics 

Philips Semiconductors

LCD controllers/drivers

Product specification

PCF2119X

9.5 Normal/icon mode operation

IM

CONDITION

0 character mode

1 icon mode

VLCD

generates VA

generates VB

9.6 Direct mode

When DM = 0, the chip is not in direct mode. Either the

internal voltage generator or an external voltage may be

used to achieve the necessary VLCD value.

When DM = 1, the chip is in direct mode. The internal

voltage generator is turned off and the VLCD output is

directly connected to the HVgen supply voltage VDD2.

The direct mode can be used to reduce the current

consumption when the required VLCD output voltage is

close to the VDD2 supply voltage. This can be the case in

icon mode or in Mux 1 : 9 (depending on LCD liquid

properties).

9.7 Voltage multiplier control

S[1:0]

A software configurable voltage multiplier is incorporated

and can be set via ‘Set HVgen stages’ command.

The voltage multiplier control can be used to reduce

current consumption by disconnecting internal voltage

multiplier stages (depending on the required VLCD output

voltage).

9.11 Set VLCD

The VLCD value is programmed by instruction. Two on-chip

registers hold VLCD values for the character mode and the

icon mode respectively (VA and VB). The generated VLCD

value is independent of VDD, allowing battery operation of

the chip.

VLCD programming:

1. Send ‘function set’ instruction with H = 1

2. Send ‘set VLCD’ instruction to write to voltage register:

a) DB7, DB6 = 10: DB5 to DB0 are VLCD of character

mode (VA)

b) DB7, DB6 = 11: DB5 to DB0 are VLCD of icon mode

(VB)

c) DB5 to DB0 = 000000 switches VLCD generator off

(when selected)

d) During ‘display off’ and power-down the VLCD

generator is also disabled.

3. Send ‘function set’ instruction with H = 0 to resume

normal programming.

9.12 Reducing current consumption

Reducing current consumption can be achieved by one of

the options given in Table 11.

When VLCD lies outside the VDD range and must be

generated, it is usually more efficient to use the on-chip

generator than an external regulator.

9.8 Screen configuration

L: default is L = 0.

L = 0: the two halves of a split screen are connected in a

standard way i.e. column 1/81, 2/82 to 80/160.

L = 1: the two halves of a split screen are connected in a

mirrored way i.e. column 1/160, 2/159 to 80/81. This

allows single layer PCB or glass layout.

9.9 Display configuration

P, Q: default is P, Q = 0.

P = 1: mirrors the column data.

Q = 1: mirrors the row data.

Table 11 Reducing current consumption

ORIGINAL MODE

Character mode

Display on

HV generator operating

Any mode

ALTERNATIVE MODE

icon mode (control bit IM)

display off (control bit D)

direct mode

power-down (PD pad)

Table 12 Use of the VA and VB registers

MODE

VA

Normal operation VLCD character

mode

VB

VLCD icon mode

9.10 TC1 and TC2

Default is TC1 and TC2 = 0. This selects the default

temperature coefficient for the internally generated VLCD.

TC1 and TC2 = 10, 01 and 11 selects alternative

temperature coefficients 1, 2 and 3 respectively.

2003 Jan 30

32

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