STV9937 datasheet(28/49 Pages) STMICROELECTRONICS

No de pièce	STV9937

Description	120-MHz On-Screen Display for Monitors including PictureBooSTTM and 4 True Independent Window Displays

PDF	49 Pages

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Fabricant	STMICROELECTRONICS [STMicroelectronics]

Site Internet	http://www.st.com

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RAM Specification

STV9937

28/49

The default window RAM allocations are listed in Table 31.

Window 1: 10 blocks of 32 words = 320 characters (ALW1 = 9).

Window 2: 4 blocks of 32 words = 128 characters (ALW2 = 3).

Window 3: 3 blocks of 32 words = 96 characters (ALW3 = 2).

Window 4: the remaining RAM (3 blocks = 96 characters).

5.4

Window Reset

All the RAM data from one of the four OSD windows can be reset by writing to bits RESETW[3:0].

When the RESETW bit is set to 1, all the RAM data in the allocation memory space of the

corresponding OSD window is reset. These bits are automatically cleared when the RAM allocation

reset is finished.

Table 31: Window RAM Default Values

ALWi

Default

Description

ALW1

320 Characters (10 blocks)

ALW2

128 Characters (4 blocks)

ALW3

96 Characters (3 blocks)

Table 32: RAM Allocation Enable and Reset

FWR

FAC

Default

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

80h

0Bh

RESETW[3:0]

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