
User’s Manual  U15862EJ3V0UD
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CHAPTER 17   CLOCKED  SERIAL  INTERFACE  A  (CSIA)  WITH
AUTOMATIC  TRANSMIT/RECEIVE  FUNCTION
The number of CSIA channels incorporated differs as follows depending on the product.
Product Name
V850ES/KF1
V850ES/KG1
V850ES/KJ1
Number of channels
1 channel (CSIA0)
2 channels (CSIA0, CSIA1)
17.1  Functions
CSIAn has the following three modes.
 Operation stop mode
 3-wire serial I/O mode
 3-wire serial I/O mode with automatic transmit/receive function
(1) Operation stop mode
This mode is used when serial transfer is not performed and can enable a reduction in the power
consumption.
(2) 3-wire serial I/O mode (MSB/LSB-first selectable)
This mode is used to transfer 8-bit data using three lines: a serial clock pin (SCKAn) and two serial data pins
(SIAn and SOAn).
The processing time of data transfer can be shortened in the 3-wire serial I/O mode because transmission
and reception can be simultaneously executed.
In addition, whether 8-bit data is transferred MSB or LSB first can be specified, so this interface can be
connected to any device.
(3) 3-wire serial I/O mode with automatic transmit/receive function (MSB/LSB-first selectable)
This mode is used to transfer 8-bit data using three lines: a serial clock pin (SCKAn) and two serial data pins
(SIAn and SOAn).
The processing time of data transfer can be shortened in the 3-wire serial I/O mode because transmission
and reception can be simultaneously executed.
In addition, whether 8-bit data is transferred MSB or LSB first can be specified, so this interface can be
connected to any device.
Data can be transferred to/from a display driver etc. without using software since a 32-byte transfer buffer
RAM is incorporated.
 Master mode/slave mode selectable
 Transfer data length:  8 bits
 MSB/LSB-first selectable for transfer data
 Automatic transmit/receive function:
Number of transfer bytes can be specified between 1 and 32
Transfer interval can be specified (0 to 63 clocks)
Single transfer/repeat transfer selectable
 On-chip dedicated baud rate generator (6/8/16/32 divisions)