Differences

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--- boards:ecb:vga3:vga3 [2017/05/29 14:16]
jcoffman
+++ boards:ecb:vga3:vga3 [2017/07/18 21:45] (current)
wwarthen
@@ Line 10: / Line 10: @@
 <font 16px/inherit;;inherit;;inherit>The color attribute display is the same as the CVDU; i.e., the color palette is fixed. However, attributes are stored with characters (char at even addresses, attributes at char address+1), as on the IBM PC display adapters. One bit of the background color may alternately be used as a 9th character code bit, allowing for 512 byte character sets. Normal operation is with 256 (8-bit) characters.</font>
+===== Keyboard Controller =====
+As on the CVDU, a PS/2 keyboard may be attached to an 8242 keyboard controller chip. The VIA chip, as shown in the photo above, has proved to be very reliable. The keyboard generates interrrupts on the ECB bus on B_/INT, or B_/IR1 when an interrupt controller is present. IRQ1 is the channel used on the IBM PC's.
+===== Screen Display Samples =====
+==== 80 x 25 @ 70hz on a wide display: ====
+{{:boards:ecb:vga3:vga3-ibm-font_0899.jpg?nolink&1000x600}}
+===   ===
+==== 80 x 30 @ 60hz on a wide display (a 512 character font is in use): ====
+{{:boards:ecb:vga3:vga3-zap512_0907.jpg?nolink&1000x616}}