LIV2/VGA-6502
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Update README.md

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Matt Harlum 2020-09-18 17:24:39 +02:00 committed by GitHub
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@ -40,7 +40,7 @@ Example: "Hello world!" with a green foreground and black background would be st
'H'|$0A|'e'|$0A|'l'|$0A|'l'|$0A|'o'|$0A|' '|$0A|'w'|$0A|'o'|$0A|'r'|$0A|'l'|$0A|'d'|$0A|'!'|$0A|
## Registers
**All registers are currently read-only as I did not have enough space in the CPLD to allow reading from the registers.**
**All registers are currently write-only as I did not have enough space in the CPLD to allow reading from the registers.**
$DF00: Register Pointer
$DF01: Register set by Register pointer
@ -52,12 +52,12 @@ $DF01: Register set by Register pointer
|$03|Cursor location (Low byte)|
|$04|Cursor location (High byte)|
### Register pointer (read only)
### Register pointer (write only)
To access a register you first need to write the register address to the register pointer (default: $DF00), then read/write the register at (default: $DF01)
### Memory Start address (read only)
### Memory Start address (write only)
This register pair forms a 16-bit memory address defining the start of the visual screen, i.e at the start of each frame the VGA controller begins reading characters from here
### Control Register (read only)
### Control Register (write only)
The control register configures various settings for the VGA controller
@ -75,5 +75,5 @@ The control register configures various settings for the VGA controller
**Mode**: Mode 0: 640x480, Mode 1: 640x400 (mode 1 will select the 8x8 fonts from the CGROM)
**Character Height**: Character height, Default: 0xF (16 pixels)
### Cursor location (read only)
### Cursor location (write only)
This register pair forms a 16-bit address defining where the cursor should be displayed