S3C2500B
DES/3DES
11-9
11.3.9 DES/3DES INPUT/OUTPUT DATA FIFO REGISTER
Table 11-14. DES/3DES Input Data FIFO Description
Bit Number
Bit Name
Description
[31:0]
DESINFIFO
This FIFO can be filled by CPU or DMA (depends on control register
value). This FIFO consists of 8 words. If data are transferred by
DMA the 4-word burst transaction (DESCON[7] is zero, and
DCON#[5] is one) is recommended. Otherwise, if data are
transferred by CPU, the 2-word transaction (DESCON[7] is one) is
recommended.
If DESCON[3] is zero, the 1
st
written data is the left half of data to
be encrypted/decrypted, bit[1:32]. The second one is the right half of
data to be encrypted/decrypted, bit[33:64]. Otherwise, if
DESCON[3] is one, the 1
st
written data is the right half of data to be
encrypted/decrypted, bit[33:64]. The second one is the left half of
data to be encrypted/decrypted, bit[1:32].
The byte order in the DESINFIFO is LSB first. That is, the LSB byte
is stored to DESINFIFO[31:24]. If you need to swap the byte order,
you can control it by using DESCON[10]. If DESCON[10] is set, the
written data to the DESINFIFO is automatically byte-swapped.
Otherwise, the written data have the original byte order.
Table 11-15. DES/3DES Output Data FIFO Description
Bit Number
Bit Name
Description
[31:0]
DESOUTFIFO
This FIFO can be read by CPU or DMA (depends on control register
value). This FIFO consists of 8 words. If data are transferred by
DMA the 4-word burst transaction (DESCON[7] is zero, and
DCON#[5] is one) is recommended. Otherwise, if data are
transferred by CPU, the 2-word transaction (DESCON[7] is one) is
recommended.
If DESCON[3] is zero, the 1
st
read data is the left half of data
encrypted/decrypted, bit[1:32]. The second one is the right half of
data encrypted/decrypted, bit[33:64]. Otherwise, if DESCON[3] is
one, the 1
st
read data is the right half of data encrypted/decrypted,
bit[33:64]. The second one is the left half of data
encrypted/decrypted, bit[1:32].
The byte order in the DESOUTFIFO is LSB first. That is the LSB
byte is read from DESOUTFIFO[31:24]. If you need to swap the
byte order, you can control it by using DESCON[10]. If
DESCON[10] is set, the read data from the DESOUTFIFO is
automatically byte-swapped. Otherwise, the read data have the
original byte order.
Summary of Contents for S3C2500B
Page 2: ...S3C2500B 32 BIT RISC MICROPROCESSOR USER S MANUAL Revision 1 ...
Page 17: ......
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Page 80: ...PRODUCT OVERVIEW S3C2500B 1 46 NOTES ...
Page 296: ...MEMORY CONTROLLER S3C2500B 5 60 NOTES ...
Page 531: ...GDMA CONTROLLER S3C2500B 12 24 NOTES ...
Page 593: ...I O PORTS S3C2500B 15 12 NOTES ...