Справочник Пользователя для Samsung S3C2440A

The CLKVAL register value determines the frequency of VCLK and frame rate. 

Frame Rate = 1/ [ { (VSPW+1) + (VBPD+1) + (LIINEVAL + 1) + (VFPD+1) } x {(HSPW+1) + (HBPD +1) 

                   + (HFPD+1) + (HOZVAL + 1) } x { 2 x ( CLKVAL+1 ) / ( HCLK ) } ] 

For applications, the system timing must be considered to avoid under-run condition of the fifo of the lcd controller 
caused by memory bandwidth contention. 
 

TFT Resolution: 240 x 240, 

VSPW =2, VBPD =14, LINEVAL = 239, VFPD =4 

HSPW =25, HBPD =15, HOZVAL = 239, HFPD =1 

CLKVAL = 5 

HCLK = 60 M (hz) 

The parameters below must be referenced by LCD size and driver specifications:  

VSPW, VBPD, LINEVAL, VFPD, HSPW, HBPD, HOZVAL, and HFPD  

If target frame rate is 60–70Hz, then CLKVAL should be 5. 

So, Frame Rate = 67Hz