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I am using the FT801 (datasheet) to drive a Newhaven 4.3" TFT display (datasheet). The TFT datasheet specifies the normal timing parameters (hsync/vsync peroid, front porch, back porch) on page 6. However, the FT801 video driver datasheet (pg 37-42) defines timing registers that are named very differently (HSYNC0, HSYNC1, HOFFSET).I am not clear on the relationship between these two different sets of timing parameters. Could someone please clarify this?

TFT timing

FT801 Registers

VSYNC1: The value of these bits specifies how many lines for signal VSYNC takes at the start of new frame

VSYNC0: The value of these bits specifies how many lines for the high state of signal VSYNC takes at the start of new frame.

VOFFSET: The value of these bits specifies how many lines takes after the start of new frame.

VCYCLE: The value of these bits specifies how many lines in one frame.

HSYNC1: The value of these bits specifies how many PCLK cycles for HSYNC during start of line.

HSYNC0: The value of these bits specifies how many PCLK cycles of HSYNC high state during start of line.

HOFFSET: These bits are the number of total PCLK cycles per horizontal line scan.

HCYCLE: The value of these bits specifies how many lines in one frame.

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Looking at the timing diagrams for the two devices:

Horizontal

HSYNC0 appears to equate to the front porch timing.

HSYNC1 is the total time for for HSYNC and HSYNC will be driven low for HSYNC1 - HSYNC0. For your display (which wants a single clock) this means that HSYNC1 should be HSYNC0 + 1.

HCYCLE appears to be the number of clocks for a complete horizontal scan line (the sum of HSYNC and display pixel clocks) so typically 525.

REG_HOFFSET is the sum of front porch, Thw and back porch and defines when pixels are driven relative to the start of HSYNC (which starts at the start of the front porch).

Vertical

These are very similar.

VSYNC0 is the vertical front porch and VSYNC1 is the total VSYNC clocks; VSYNC will be driven low for VSYNC1 - VSYNC0 clocks.

VOFFSET is the sum of vertical front porch, vertical sync pulse width and vertical back porch.

VCYCLE appears to be the total number of vertical scans per frame.

I referenced the timing diagrams on page 7 of the display data sheet and pages 15 and 16 of the FTDI driver datasheet.

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