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.

We want to get the Vsync to about 60hz

By default, the 'internal' LCD sync rate is 117 Hz

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

This is set by the HW_CLKCTRL_PIX register

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

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

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

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

Actually, to get the closest to 60 Hz. I went with HW_CLKCTRL_PIX=0x37 (so says the tek 'scope)

How the Hsync is 17.08 KHz (we want 2x that 31.46 KHz)