NEC PD17062 - Manual (Page 254)

254
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PD17062
20.4.5 Cautions in Specifying VRAM Data
(1) Reset the IDCEN flag to 0 before specifying VRAM data.
(2) The VRAM data must begin at 00H in BANK1.
(3) Do not set VRAM data at 7
×
H in BANK1 or BANK2.
(4) Always set control data at the beginning of a screen. To prevent a program error, control data should
be set at the beginning of each row. Otherwise, the previous control data remains effective.
(5) Data setting
(a) The character pattern select data should be set at VRAM addresses sequentially starting at the lowest
address so that the corresponding display begins at the upper left corner of the screen.
(b) Control data can be used up to three times on each row.
(c) The character pattern data that is modified by the control data begins after the control data select data.
The horizontal start position data and vertical start position data correspond to only a character that
follows immediately the control data select data; the other characters are output consecutively.
(d) Always specify carriage return data at the end of a row.
(e) Always specify two carriage return data items at the end of a screen.