Commodore 128 Programmer's Reference Manual page 323

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PROGRAMMING THE 80-COLUMN (8563) CHIP 313
6. Finally, place the number of successive memory locations you want to write
to 8563 RAM in register 30.
1 I At this point, the 8563 writes the data in register 31 starting from the location deter
mined by registers 18 and 19 through the number of successive memory locations specified
r*> by register 30. The contents of registers 18 and 19 are automatically incremented to access
j j the next location to be written. Upon completion of the Block Write, registers 18 and 19
contain the last address plus one of the 8563 RAM locations in which it was written.
^ Note that one write cycle follows the initial write operation to register 31;
I | therefore, the quantity written to register 30 should be one less than the number of 8563
1 \ memory locations in which you want to write.
H BLOCK COPY
) j The Block Copy feature copies (reads and writes) data from one section of 8563 RAM
to another. To copy a block of 8563 RAM:
' . j 1. Place the destination address, where copying in RAM begins, into registers
1 18 (high byte) and 19 (low byte).
2. Wait for the Update Status Ready bit to become high (1).
P 3. Set (1) bit 7 of register 24, which selects the Block Copy feature. At this
i point, the 8502 writes the initial source address for the block copy to registers
32 (high byte) and 33 (low byte).
r-> 4. Place the number of successive memory locations to copy into register 30.
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The 8563 reads the contents of the first source address and writes the data to the
first destination address. The 8563 RAM addresses are automatically incremented and
PJ copying continues until the number of memory locations specified by register 30 are copied.
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READING FROM 8563 RAM
' I The process of reading from 8563 RAM is the same as reading from a register, except
' < you read from the data register, register 31.
- PROGRAMMING THE 8563 CURSOR
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The 80-column cursor is programmable in its image and movement. First, the cursor
image may be programmed in four different ways. Bits 6 and 5 of register 10 control the
P following four characteristics of the cursor:
BIT VALUE CHARACTERISTIC
6 5
0 0 Solid cursor
0 1 No visible cursor
1 0 Slow cursor blink rate (Vie the frame rate)
1 1 Fast cursor blink rate (Vk the frame rate)