551
Clocked Serial Interface (CSIB)
Chapter 17
Preliminary User’s Manual U17566EE1V2UM00
(5)
CBnRX - CSIBn receive data register
The CBnRX register is a 16-bit buffer register that holds receive data.
Access
This register can be read-only in 16-bit units.
If the transfer data length is 8 bits, the lower 8 bits of this register are read-only
in 8-bit units as the CBnRXL register.
Address
<base> + 4
H
Initial Value
0000
H
. This register is cleared by any reset.
In addition to reset input, the CBnRX register can be initialized by clearing (to
0) the CBnPWR bit of the CBnCTL0 register.
The receive operation is started by reading the CBnRX register in the
reception enabled status.
(6)
CBnTX - CSIB transmit data register
The CBnTX register is a 16-bit buffer register used to write the CSIBn transfer
data.
Access
This register can be read/written in 16-bit units.
If the transfer data length is 8 bits, the lower 8 bits of this register are read/write
in 8-bit units as the CBnTXL register.
Address
<base> + 6
H
Initial Value
0000
H
. This register is cleared by any reset.
In addition to reset input, the CBnTX register can be initialized by clearing (to
0) the CBnPWR bit of the CBnCTL0 register.
The transmit operation is started by writing data to the CBnTX register in the
transmission enabled status.
Note
The communication start conditions are shown below:
• Transmission mode (CBnTXE bit = 1, CBnRXE bit = 0):
Write to CBnTX register
• Transmission/reception mode (CBnTXE bit = 1, CBnRXE bit = 1):
Write to CBnTX register
• Reception mode (CBnTXE bit = 0, CBnRXE bit = 1):
Read from CBnRX register
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Receive data
R
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Transmit data
R/W
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