Typewriter User Manual

5- 82 MC68340 USER’S MANUAL MOTOROLA

Operand Data:

None

Result Data:

Requested data is returned as either a word or long word. Byte data is returned in the

least significant byte of a word result. Word results return 16 bits of significant data;

long-word results return 32 bits. Status of the read operation is returned as in the READ

command: $0xxxx for success, $10001 for bus or address errors.

5.6.2.8.11 Fill Memory Block (FILL). FILL is used in conjunction with the WRITE

command to fill large blocks of memory. An initial WRITE is executed to set up the starting

address of the block and to supply the first operand. Subsequent operands are written

with the FILL command. The initial address is incremented by the operand size (1, 2, or 4)

and is saved in a temporary register. Subsequent FILL commands use this address,

increment it by the current operand size, and store the updated address back in the

temporary register.

NOTE

The FILL command does not check for a valid address in the

temporary register—FILL is a valid command only when

preceded by another FILL or by a WRITE command.

Otherwise, the results are undefined. The NOP command can

be used for intercommand padding without corrupting the

address pointer.

The size field is examined each time a FILL command is given, allowing the operand size

to be altered dynamically.

Command Format:

1514131211109876543210

00011100OP SIZE 000000

Frees

cale Semiconductor,

Freescale Semiconductor, Inc.

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