PCF8545ATT datasheet(9/54 Pages) NXP

9 / 54 page

PCA8576F

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Product data sheet

Rev. 3 — 3 December 2014

9 of 54

NXP Semiconductors

PCA8576F

Automotive 40 × 4 LCD driver

7.3 Display RAM

The display RAM is a static 40

 4-bit RAM which stores LCD data.

There is a one-to-one correspondence between

• the bits in the RAM bitmap and the LCD segments/elements

• the RAM columns and the segment outputs

• the RAM rows and the backplane outputs.

A logic 1 in the RAM bitmap indicates the on-state of the corresponding LCD element;

similarly, a logic 0 indicates the off-state.

The display RAM bit map, Figure 4, shows the rows 0 to 3 which correspond with the

backplane outputs BP0 to BP3, and the columns 0 to 39 which correspond with the

segment outputs S0 to S39. In multiplexed LCD applications the segment data of the first,

second, third and fourth row of the display RAM are time-multiplexed with BP0, BP1, BP2,

and BP3 respectively.

The display RAM bitmap shows the direct relationship between the display RAM column and the

segment outputs; and between the bits in a RAM row and the backplane outputs.

Fig 4.

Display RAM bit map

PCF8545ATT Datasheet(PDF) 9 Page - NXP Semiconductors