-
Video Circuit
The Video circuit in the Blackvoxel ASM virtual machine is very simple. This circuit support direct memory access (DMA) and can trigger interrupt when a new image is displayed.
Video Circuit Registers.
0x80000100 : VIDEO_MODE
0x80000104 : VIDEO_ADDRESS
0x80000108 : VIDEO_CONTROLVIDEO_MODE (0x80000100) : Video Mode
This register select the video mode. The following video modes are supported (More can be added in the future):
0 : No display. This is the default at circuit reset.
1 : Text Mode 40x30, one byte per char. 8x8 Matrix on 320 * 240 pixels display.VIDEO_ADDRESS (0x80000104) Video Memory Address
Contains the address of the start of the video memory. The data in this portion of memory will be displayed. The circuit uses direct memory access (DMA) to retrieve the data to display in memory.
VIDEO_CONTROL (0x80000108) Video Control Informations
This register control some behavior of the circuit like the interrupts.
Bit Behavior 0 Interrupt Enable. 0=Disabled / 1=Enabled.
Enable interrupt when the image is displayed1 Interrupt Triggered. 1 = Interrupt Triggerred. 0 = No interrupt Triggered.
This bit is set to 1 when an interrupt is triggered by the video circuit.
Must be reset to 0 by the Interrupt processing program.2-31 Unused. Do not use, reserved for futur use. -
Video Circuit
