IDMA Channels
MC68360 USER’S MANUAL
—CSR1 = $FF. Clear any CSR bits that are currently set.
—CMAR1 = $00. Disable interrupts for this example.
—CMR1 = $47A1. Internal maximum transfer rate; starts IDMA.
Example 2. This more complicated example shows how packing is performed when the
source and destination sizes are the same—long word. This example also shows the entire
7-byte DHR in use. The source address is $00000000, and the destination address is
$20000003. The number of bytes to be transferred is 16.
IDMA channel 1 initialization required for this example:
ICCR = $0720. Recommended normal configuration.
FCR1 = $89. Source function code is 1000; destination function code is 1001.
SAPR1 = $00000000. Source address.
DAPR1 = $20000003. Destination address.
BCR1 = $00000010. Byte transfer count.
CSR1 = $FF. Clear any CSR bits that are currently set.
CMAR1 = $00. Disable interrupts for this example.
CMR1 = $4701. Internal maximum transfer rate; starts IDMA.
Example 3. This example shows how packing operates when the source and destination
sizes are different. The source address is $00000002, and the destination address is
$20000002. The source size is long word, and the destination size is byte. The number of
bytes to be transferred is 8.
Bus Access #
Address (Hex)
Operation
No. Bytes
No. Bytes in DHR
1
$00000001
Read
1
2
$00000002
Read
2
3
$20000000
Write
2
1
4
$00000002
Write
1
0
Bus Access #
Address (Hex)
Operation
No. Bytes
No. Bytes in DHR
1
$00000000
Read
4
2
$20000003
Write
1
3
$00000004
Read
4
7
4
$20000004
Write
4
3
5
$00000008
Read
4
7
6
$20000008
Write
4
3
7
$0000000C
Read
4
7
8
$2000000C
Write
4
3
9
$20000010
Write
2
1
10
$20000012
Write
1
0
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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