Transfer LVDS to HDMI

Intel VGA I.G.D 支援的輸出格式，是以支援標準的輸出格式為主，例如640x480 / 1024x768 / 1280 x 1024…。，。

但是HDMI卻是TV的規格，卻是480i / 720P /1080i /1080p。

所以為了讓PC可以輸出到TV走HDMI，除了硬體的訊號轉換外，還需要修改VGA BIOS。

Intel Standard VGA BIOS雖然不支援1280 x 720的解析度,但是VGA BIOS是可以利用BMP修改的,要修改的是LFP Panel的DTD Timings.

而DTD Timings就是依照VESA EDID的規範做的，要填的有18-Byte。

http://en.wikipedia.org/wiki/Extended_display_identification_data

" The table is the 18-byte DTD structure defined in the VESA EDID version 1.x."

DB ? ; Low Byte of DClk in 10 KHz

DB ? ; High Byte of DClk in 10 KHz

DB ? ; Horizontal Active in pixels, LSB

DB ? ; Horizontal Blanking in pixels, LSB

DB ? ; Bit 7-4: Upper 4 bits of Hor. Active

; Bit 3-0: Upper 4 bits of Hor. Blanking

DB ? ; Vertical Active in lines, LSB

DB ? ; Vertical Blanking in lines, LSB

DB ? ; Bit 7-4: Upper 4 bits of Vert. Active

; Bit 3-0: Upper 4 bits of Vert. Blanking

DB ? ; HSync Offset from Hor. Blanking in pix., LSB

DB ? ; HSync Pulse Width in pixels, LSB

DB ? ; Bit 7-4: Lower 4 bits of VSync Offset

; Bit 3-0: Lower 4 bits of VSync Pulse Width

DB ? ; Bit 7-6: Upper 2 bits of HSync Offset

; Bit 5-4: Upper 2 bits of HSync Pulse Width

; Bit 3-2: Upper 2 bits of VSync Offset

; Bit 1-0: Upper 2 bits of VSync Pulse Width

DB ? ; Horizontal Image Size, LSB

DB ? ; Vertical Image Size, LSB

DB ? ; Bit 7-4: Upper 4 bits of Hor. Image Size

; Bit 3-0: Upper 4 bits of Vert. Image Size

DB 0 ; Horizontal Border in pixels

DB 0 ; Vertical Border in lines

DB ? ; Flags:

; Bit 7: 0 = Non-interlaced, 1 = Interlaced

; Bit 6-5: 00 = Reserved

; Bit 4-3: 11 = Digital Separate

; Bit 2: Vertical Polarity (0 = Negative, 1 = Positive)

; Bit 1: Horizontal Polarity (0 = Negative, 1 = Positive)

; Bit 0: 0 = Reserved

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DB 01h ; Low Byte of DClk in 10 KHz

DB 1dh ; High Byte of DClk in 10 KHz

;Pixel Clock = Horizontal x Vertical x Frame

;Pixel Clock = 1650 x 750 x 60 = 74.25 MHz

DB 00h ; Horizontal Active in pixels, LSB

DB 72h ; Horizontal Blanking in pixels, LSB

DB 51h ; Bit 7-4: Upper 4 bits of Hor. Active

; Bit 3-0: Upper 4 bits of Hor. Blanking

;Horizontal Active -> 1280 = 0500h

;Horizontal Blanking -> 370 = 0172h

DB D0h ; Vertical Active in lines, LSB

DB 1Eh ; Vertical Blanking in lines, LSB

DB 20h ; Bit 7-4: Upper 4 bits of Vert. Active

; Bit 3-0: Upper 4 bits of Vert. Blanking

;Vertical Active -> 720 = 2D0h

;Vertical Blanking -> 30 = 01Eh