PCF21219DUGR datasheet(29/107 Pages) NXP

29 / 107 page

PCA2117

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Product data sheet

Rev. 4 — 8 April 2015

29 of 107

NXP Semiconductors

PCA2117

Automotive LCD driver for character displays

8.2.2 Reset pin function

The reset pin (RST) of the PCA2117 resets all the registers to their default state. The reset

state is given in Table 34. The RAM contents remain unchanged. After the reset signal is

released, the Initialize command must be sent to complete the initialization of the chip.

8.2.3 Power-down pin function

When connected to VDD1, the internal circuits are switched off, leaving only 2 A (typical)

as an overall current consumption. When connected to VSS1, the PCA2117 runs or starts

up to normal mode again. For the start-up and power-down sequences, see Section 8.2.4

and Section 8.2.5.

8.2.4 Recommended start-up sequences

This section describes how to proceed with the initialization of the chip in different

application modes.

When using the internal VLCD generation, the display must not be enabled before the

generation of VLCD with the internal charge pump is completed. Otherwise unwanted

display artifacts may appear on the display.

(1) The QPR flag (see Table 12) indicates if the programmed LCD voltage value was reached. The

latency time depends on the external capacitor on the VLCD pins. For a capacitor of 100 nF a delay

of 50 ms to 60 ms is expected.

Fig 6.

Recommended start-up sequence when using the internal charge pump and the

internal clock signal

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