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MTV021 Revision 5.0 6/29/1999

MTV021

MYSON

TECHNOLOGY

Note:" v " means the nth line in the character would be repeated once, while " - " means the nth line in the

character would not be repeated.

3.4 Horizontal display control

The horizontal display control is used to generate control timing for horizontal display based on double char-

acter width bit (CWS), horizontal positioning register (HORD), horizontal resolution register (HORR), and

HFLB input. A horizontal display line consists of (HORR*12) dots which include 360 dots for 30 display char-

acters and the remaining dots for blank region. The horizontal delay starting from HFLB leading edge is calcu-

lated with the following equation,

Horizontal delay time = ( HORD * 6 + 49) * P - phase error detection pulse width

Where P = One pixel display time = One horizontal line display time / (HORR*12)

3.5 Phase lock loop (PLL)

On-chip PLL generates system clock timing (VCLK) by tracking the input HFLB and horizontal resolution reg-

ister (HORR). The frequency of VCLK is determined by the following equation:

VCLK Freq = HFLB Freq * HORR * 12

The VCLK frequency ranges from 6MHz to 96MHz selected by (VCO1, VCO0). In addition, when HFLB input

is not present to MTV021, the PLL will generate a specific system clock, approximately 2.5MHz, by a built-in

oscillator to ensure data integrity.

3.6 Display & Row control registers

The internal RAM contains display and row control registers. The display registers have 450 locations which

are allocated between (row 0, column 0) to (row 14, column 29), as shown in Figure 4. Each display register

has its corresponding character address on ADDRESS byte, its corresponding background color, 1 blink bit

and its corresponding color bits on ATTRIBUTE bytes. The row control register is allocated at column 30 for

CH3=1

+8

CH2=1

+4

CH1=1

+2

CH0=1

+1

TABLE 3. Repeat line number of character

Repeat Line

Weight

Repeat Line #

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

+1

-

-

-

-

-

-

-

-

v

-

-

-

-

-

-

-

-

-

+2

-

-

-

-

v

-

-

-

-

-

-

-

v

-

-

-

-

-

+4

-

-

v

-

-

-

v

-

-

-

v

-

-

-

v

-

-

-

+8

-

v

-

v

-

v

-

v

-

v

-

v

-

v

-

v

-

-

+16

-

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

-

+17

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

-

+18

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

TABLE 2. Repeat line weight of character

CH6 - CH0

Repeat Line Weight