UPD17062 datasheet(249/298 Pages) RENESAS

249 / 298 page

247

µPD17062

Fig. 20-2

VRAM Data Configuration

20.4.1

ID Field

The ID field indicates the type of data in the data field.

The data field can hold the following three types of data.

(1) Character pattern select data

(2) Carriage return data

(3) Control data select data

Table 20-3

ID Field

20.4.2

Character Pattern Select Data

The character pattern is the data of an image displayed on a screen such as a TV screen. It is allocated

in the CROM area (at 0800H to 0F7FH) of program memory. The character pattern select data becomes part

(b9 to b4) of a CROM address. In other words, the 6 bits of data in the data field indicate b9 to b4 of the CROM

address.

CROM consists of BANK0 and BANK1. Note that even if the 6-bit VRAM data is the same, the CROM address

varies according to the value of the CROMBNK (b0 at 30H). If the data field contains a value of 0 (000000B),

the CROM address is 080

×H (10000000××××B) or 0C0×H (11000000××××B). Specifying the BANK of CROM

selects 080

×H or 0C0×H. Table 20-4 lists the CROM addresses that the VRAM character pattern select data

actually points to.

(b3)(b2)(b1)(b0)(b3)(b2)(b1)(b0)

ID field

Data field

Even address

Odd address

ID field

Type of data in the data field

Character pattern select data

Carriage return (return address) to BANK1 (from BANK1 to

BANK1, and from BANK2 to BANK1)

Control data

Carriage return (return address) to BANK2 (from BANK2 to

BANK2)

UPD17062 Datasheet(PDF) 249 Page - Renesas Technology Corp