Epson S1D13705 7.5 Limitations

Page 42 Epson Research and Development
Vancouver Design Center
S1D13705 Programming Notes and Examples
X27A-G-002-03 Issue Date: 02/01/22
7.5 Limitations
The only limitation to using portrait mode on the S1D13705 is that split screen ope ration is
not supported.
A comparison of the two portrait modes is as follows:
Table 7-1: Default and Alternate Portrait Mode Comparison
Item Default Portrait Mode Alternate Portrait Mode
Memory Requirements
The width of the rotated image must be
a power of 2. In most cases, a virtual
image is required where the right-hand
side of the virtual image is unused and
memory is wasted. For example, a
320x480x4bpp image would normally
require only 76,800 bytes - possible
within the 80K byte address space, but
the virtual image is 512x480x4bpp
which needs 122,880 bytes - not
possible.
Does not require a virtual image.
Clock Requirements CLK need only be as fast as the
required PCLK.
MCLK, and hence CLK, need to be 2x
PCLK. For example, if the panel requires a
3MHz PCLK, then CLK must be 6MHz.
Note that 25MHz is the maximum CLK, so
PCLK cannot be higher than 12.5MHz in
this mode.
Power Consumption Lowest power consumption. Higher than Default Mode.
Panning Vertical panning in 2 line increments. Vertical panning in 1 line increments.
Performance
Nominal performance. Note that
performance can be increased by
increasing CLK and setting MCLK =
CLK (REG[1Bh] bit 2 = 1).
Higher performance than Default Mode.
Note that performance can be increased by
increasing CLK and setting MCLK = CLK
(REG[1Bh] bit 2 = 1).