NXP Semiconductors LPC43 Series User Manual

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NXP Semiconductors LPC43 Series User Manual Manual pdf 797 page image

UM10503 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2012. All rights reserved.User manual Rev. 1.3 — 6 July 2012 797 of 1269NXP Semiconductors UM10503Chapter 27: LPC43xx LCDCursor pixel encodingEach pixel of the cursor requires two bits of information. These are interpreted as Color0,Color1, Transparent, and Transparent inverted.In the coding scheme, bit 1 selects between color and transparent (AND mask) and bit 0selects variant (XOR mask).Table 639 shows the pixel encoding bit assignments.27.7.6 Gray scalerA patented gray scale algorithm drives monochrome and color STN panels. This provides15 gray scales for monochrome displays. For STN color displays, the three colorcomponents (RGB) are gray scaled simultaneously. This results in 3375 (15x15x15)colors being available. The gray scaler transforms each 4-bit gray value into a sequenceof activity-per-pixel over several frames, relying to some degree on the displaycharacteristics, to give the representation of gray scales and color.27.7.7 Upper and lower panel formattersFormatters are used in STN mode to convert the gray scaler output to a parallel format asrequired by the display. For monochrome displays, this is either 4 or 8 bits wide, and forcolor displays, it is 8 bits wide. Table 640 shows a color display driven with 2 2/3 pixelsworth of data in a repeating sequence.5:4 (1, 0) (17, 0) (33, 0) (49, 0) (1, y) (17, y) (33, y) (49, y) (49, 63)3:2 (2, 0) (18, 0) (34, 0) (50, 0) (2, y) (18, y) (34, y) (50, y) (50, 63)1:0 (3, 0) (19, 0) (35, 0) (51, 0) (3, y) (19, y) (35, y) (51, y) (51, 63)Table 638. Buffer to pixel mapping for 64 x 64 pixel cursor formatOffset into cursor memoryData bits 0 4 8 12 (16 * y) (16 * y) +4 (16 * y) + 8 (16 * y) + 12 FCTable 639. Pixel encodingValue Description00 Color0.The cursor color is displayed according to the Red-Green-Blue (RGB) valueprogrammed into the CRSR_PAL0 register.01 Color1.The cursor color is displayed according to the RGB value programmed into theCRSR_PAL1 register.10 Transparent.The cursor pixel is transparent, so is displayed unchanged. This enables the visiblecursor to assume shapes that are not square.11 Transparent inverted.The cursor pixel assumes the complementary color of the frame pixel that is displayed.This can be used to ensure that the cursor is visible regardless of the color of theframe buffer image.