Renesas H8S/2100 Series, Hardware Manual

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Section 16 CIR Interface
Rev. 1.00 Apr. 28, 2008 Page 486 of 994
REJ09B0452-0100
16.4.2 Operation of FIFO Register
A FIFO structure provides first-in first-out operation.
Operation of the FIFO when it receives data three times (byte 0, byte 1, and byte 2 in order) and is
then read three times is as shown below.
Number of bytes
1
2
3
4
18
FIFO contents
Byte 0
H'00
H'00
H'00
.
.
. .
.
.
H'00
Number of bytes
1
2
3
4
18
FIFO contents
Byte 0
Operation for first reception
of data Operation for data reception
three times
Byte 1
Byte 2
H'00
.
.
. .
.
.
H'00
Figure 16.6 Operation when FIFO Data is Received
Number of bytes
1
2
3
4
18
FIFO Contents
Byte 1
Byte 2
H'00
H'00
.
.
. .
.
.
H'00
First read
N
umber of bytes
1
2
3
4
18
FIFO Contents
Byte 2
H'00
H'00
H'00
.
.
. .
.
.
H'00
Number of bytes
1
2
3
4
18
FIFO contents
H'00
Second read Third read
H'00
H'00
H'00
.
.
. .
.
.
H'00
Figure 16.7 Operation when FIFO Data is Read