H/V Count Timer

The H/V Count Timer can be programmed to generate an IRQ when the CRT's raster beam reaches a particular position.

The desired horizontal position should be written to HTIMEL and HTIMEH.

The desired vertical position should be written to VTIMEL and VTIMEH.

The IRQ this timer generates is sometimes called an HV-IRQ if it fires at a particular point, a V-IRQ if it fires at a particular scanline (but the dot/horizontal position is not important), or an H-IRQ if it fires at a particular dot (but the scanline is not important).

See Also

• H/V Counter Latch

Reference

• page 2-16-1 of the official Super Nintendo development manual