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====== DAC ======

The LCD breakout has 6 bit x RGB output, which we can turn into a 6-bit DAC -> RGB analog 0.7Vpp into 75 ohms
use 278 & 556 ohm resistors for the R2R ladder, this will give you ~0.7v signal when plugged into a 75 ohm termination such as a monitor. 

====== VSync ======

We want to get the Vsync to about 60hz

By default, the 'internal' LCD sync rate is 117 Hz
<code>
chumby-:/ # cat /proc/driver/chumbyfwfb/fb_stats
PXP frequency:          59 Hz
LCDIF frequency:        117 Hz
VSYNC Edge IRQs:        49077
Cur Frame Done IRQs:    49224
Missed PXP firings:     5
</code>

This is set by the  HW_CLKCTRL_PIX register

<code>
chumby-:/ # regutil -r HW_CLKCTRL_PIX
Value at 0x80040060: 0x0000001d
</code>

Lets divide the frequency by 2 which means multiplying the divider by two

<code>
chumby-:/ # regutil -w HW_CLKCTRL_PIX=0x38
Setting 0x80040060: 0x0000000e -> 0x00000038 ok
</code>

<code>
chumby-:/ # cat /proc/driver/chumbyfwfb/fb_stats
PXP frequency:          32 Hz
LCDIF frequency:        62 Hz
VSYNC Edge IRQs:        69919
Cur Frame Done IRQs:    70118
Missed PXP firings:     5
</code>
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