LCD

# 4 LCD

AGB uses a 2.9-inch-wide reflective TFT color LCD screen.

The vertical blanking interval of AGB is longer than that of DMG and CGB, and its horizontal blanking interval is fixed.

Item | Value | Interval
Display screen size | Number of dots per horizontal line | 240 dots | 57.221 s
Number of horizontal lines | 160 lines | 11.749 ms
Total number of dots | Number of dots per horizontal line | 308 dots | 73.433 s
Number of horizontal lines | 228 lines | 16.743 ms
Blanking | Number of dots per horizontal blank | 68 dots | 16.212 s
Number of horizontal lines per vertical blank | 68 lines | 4.994 ms
Scanning cycle | H interval frequency | 13.618 KHz | 73.433 s
V interval frequency | 59.727 Hz | 16.743 ms

## 4.1 LCD Status

### 4.1.1 V Counter

The VCOUNT register can be used to read which of the total of 228 LCD lines (see previous figure) is currently being rendered.

A value of 0-227 is read.

A value of 0-159 indicates that rendering is in progress; a value of 160-227 indicates a vertical blanking interval.

### 4.1.2 General LCD Status

General LCD status information can be read from bits 0-5 of the DISPSTAT register.

In addition, 3 types of interrupt requests can be generated by the LCD controller.

DISPSTAT [d15-08] V Count Setting

> Can be used to set the value used for V counter evaluation and V counter match interrupts. The range for this setting is 0-227.

DISPSTAT [d05] V Counter Match Interrupt Request Enable Flag

> Allows an interrupt request to be generated when the value of the V counter setting and the value of the line actually rendered (VCOUNT register value) agree.

DISPSTAT [d04] H-Blank Interrupt Request Enable Flag

> Allows an interrupt request to be generated during horizontal blanking.

DISPSTAT [d03] V-Blank Interrupt Request Enable Flag

> Allows an interrupt request to be generated during vertical blanking.

DISPSTAT [d02] V Counter Evaluation

> Flag indicating whether the V count setting and the V count register value match. It is set while they match and automatically reset when they no longer match.

DISPSTAT [d01] H-Blank Status

> Can check whether a horizontal blanking interval is currently in effect.

DISPSTAT [d00] V-Blank Status

> Can check whether a vertical blanking interval is currently in effect.