CL-PS7500FE
System-on-a-Chip for Internet Appliance
12.3.1 Cursor in HiRes Mode
To allow µ-pixel resolution of the cursor in HiRes mode when operating at 4-µ-pixels-per-normal-pixel,
define 2-bits-per-µ-pixel or 8-bits-per-normal-pixel. The 16 bytes of cursor data available for each raster
can then generate 64 µ-pixels of cursor. In HiRes mode the cursor palette is not used (though the border
may be programmed). Refer to Section 12.4 for more details on HiRes support.
The cursor is always positioned to align with a normal pixel.To position the cursor to a µ-pixel horizontally,
four different copies of the cursor are required: each copy defines the cursor offset by a single µ-pixel. It
is possible to define transparency to a resolution of a µ-pixel; selecting the correct cursor image, can
achieve the required position.
12.3.2 Cursor in LCD Mode
The video subsystem is capable of displaying the hardware cursor in LCD mode. However, because of
the split-screen nature of duplex LCDs, the cursor requires special attention. If the cursor is entirely in the
upper or lower half-screen, program the cursor normally, but program VCSR[14:13] as:
●
0x10 = upper half-screen
0x01 = lower half-screen)
●
If the cursor straddles the split screen, the cursor image in memory must start at the top of the lower half-
screen and end with the bottom of the upper half-screen. In this way, two contiguous images of the cursor
image are required and the start pointer moves accordingly. Four images of the cursor are required to
ensure that the resolution of one raster is maintained across the boundary. As the cursor moves from one
panel to the other, the pointer to the cursor image in memory must move. For more details, refer to
Appendix B.
When the cursor straddles the split screen, the meaning of the VCSR and VCER change.The VCER now
defines the start of cursor in the upper half-screen; the VCSR defines the end of the cursor in the lower
half-screen.The cursor actually displays in the lower half-screen from the start of display until VCSR, then
again in the upper half-screen from VCER until the end of display.This mode is selected by programming
VCSR[14:13] = 0x11. For more discussion on how to use CL-PS7500FE with dual-panel LCD screens,
refer to Appendix B.
12.4 HiRes Support
The CL-PS7500FE can support color screens with resolutions above 1024 × 768 pixels. For higher reso-
lutions, externally serializing the data is required to produce monochrome (or gray-level) pictures. In this
scheme, one 16-ns pixel could theoretically be serialized to make eight 2-ns pixels (that is, approximately
500 MHz). This is dependent on the availability of external hardware capable of generating a serial bit-
stream at this frequency.
12.4.1 CL-PS7500FE Support for HiRes Mode
When the hrm bit (EREG[14]) is set and EREG[1:0] is set to the value ‘0x10’, the CL-PS7500FE outputs
8 bits of data for every normal pixel on the ED[7:0] port. These bits can then be serialized to form a high-
frequency, monochrome pixel stream; alternatively they can be serialized to 2 or 4 bits able to drive a high-
speed, monochrome DAC for gray-level displays.With the pixel clock running at a fundamental frequency
of approximately 100 MHz, the external serial clock can run at up to several hundred MHz.For the external
circuit to be able to synchronize to the CL-PS7500FE output data, the CL-PS7500FE also outputs a pixel
clock synchronous to the data stream when EREG[14] is set.
June 1997
127
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