LM1237 datasheet(21/42 Pages) NSC

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LM1237 Address Map

TABLE 4. Character ROM Address Map

Address Range

R/W

Description

0x0000–0x2FFF

ROM Character Fonts, 190 two-color Character Fonts that are read-only. The format

of the address is as follows:

A15–A14: Always zeros.

A13–A6: Character value (0x00–0xBF are valid values)

A5–A1: Row of the character (0x00–0x11 are valid values)

A0: Low byte of line when a zero. High byte of line when a one.

The low byte will contain the first eight pixels of the line with data Bit 0 corresponding

to the left most bit in the Character Font line. The high byte will contain the last four

pixels and data. Bits 7–4 are “don’t cares”. Data Bit 3 of the high byte corresponds to

the right most pixel in the Character Font line.

0x3000–0x3FFF

ROM Character Fonts, 64 four-color Character Fonts that are read-only. The format of

the address is as follows:

A15–A14: Always zeros.

A13–A6: Character value (0xC0–0xFF are valid values)

A5–A1: Row of the character (0x00–0x11 are valid values)

A0: Low byte of line when a zero. High byte of line when a one.

The low byte will contain the first eight pixels of the line with data Bit 0 corresponding

to the left most bit in the Character Font line. The high byte will contain the last four

pixels and data Bits 7–4 are “don’t cares”. Data Bit 3 of the high byte corresponds to

the right most pixel in the Character Font line.

NOTE: The value of Bit 0 of the Character Font Access Control Register (Address

0x8402) is a zero, it indicates that the Bit 0 data value of the four-color pixels is being

accessed via these addresses. When the value of Bit 0 of the Access Control Register

is a one, it indicates that the Bit 1 data value of the four-color pixel is being accessed

via these addresses.

0x4000–0x7FFF

—

Reserved.

TABLE 5. Display Page RAM Address Map

Address Range

R/W

Description

0x8000–0x81FF

R/W

Display Page RAM Characters. A total of 512 display characters, skipped line,

end-of-row and end-of-window character codes may be supported via this range.

To support skipped lines and character attributes a number of special case rules are

used when writing to this range. (Refer to the Display Page RAM section of this

document for more details.)

Preamp Interface Registers

TABLE 6. OSD Interface Registers

Address

Default

Fonts - 2 Color

0x0000–

0x2FFE

PIXEL (7:0)

XXXX

PIXEL (11:8)

Fonts - 4 Color

0x3000–

0x3FFE

PIXEL (7:0)

XXXX

PIXEL (11:8)

Display Page

0x8000–

0x83FF

CHAR_CODE[7:4] or reserved

CHAR_CODE[3:0] or ATTR_CODE

FRMCTRL1

0x8400

0x10

CDPR

D2E

D1E

OSE

FRMCTRL2

0x8401

0x80

PIXELS_PER_LINE (2:0)

BLINK_PERIOD (4:0)

CHARFONTACC

0x8402

0x00

XXXXXX

ATTR

FONT4

VBLANKDUR

0x8403

0x10

VBLANK_DURATION (6:0)

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