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Epson Research and Development
Vancouver Design Center
SED1352
LCD Panel Options / Memory Requirements
X16-AN-005-07
Issue Date: 98/10/08
2 CONFIGURATION EQUATIONS
2.1 Example:
LCD panel resolution:
640x240
LCD panel configuration
4 bit, Single drive panel
LCD Gray Shades
4
Desired Frame-rate:
~70Hz
2.1.1 Input Clock Requirement
For a frame rate of 70Hz, the input clock (or pixel clock) frequency can be calculated as following,
f
OSC
= input clock
f
OSC
= Frame Rate * (# of horizontal 16) * (# of vertical lines + 4)
Therefore;
f
OSC
= 70 * (640 + 16) * (240 + 4)
f
OSC
= 11.2MHz
Note
1. Due to oscillator frequency availability, a 12MHz oscillator is selected thus producing a slightly
higher frame-rate (~75Hz).
2. For a detailed description of the frame rate formula, see section 9.3 of the SED1352 Hardware Func-
tional Specification, drawing office number X16-SP-001-xx.
2.2 SRAM Size and Access Time Requirements
2.2.1 SRAM Size
Memory Size (bytes) =
i.e., 4 gray shades = 2 bits / pixel, therefore 1 byte (8 bits)
=
4 pixels
Therefore:
Memory size (bytes) = (640 * 240) / 4
Memory size (bytes) = 37.5 K bytes.
Note
For a detailed description of the memory size requirement, see section 9.4 of the SED1352 Hardware Functional
Specification, drawing office number X16-SP-001-xx.
(# of Horizontal pixels)* (# of Vertical pixels)
8 (# of bits/pixel)
/