CHAPTER 11 SERIAL INTERFACE FUNCTION
User’s Manual U15109EJ3V0UD
354
11.4.4
Operation
CSIn is has the following two operation modes (n = 5, 6).
•
Single transfer mode
•
Repeat transfer mode
(1) Single transfer mode
(a) Usage
In the receive-only mode (TRMDn bit of CSIMn register = 0), transfer is started by reading
Note
1
the receive
data buffer register (SIRBn/SIRBLn) (n = 5, 6).
In the transmit/receive mode (TRMDn bit of CSIMn register = 1), transfer is started by writing
Note
2
to the
transmit data buffer register (SOTBn/SOTBLn).
In the slave mode, operation must be enabled beforehand (CSIEn bit of CSIMn register = 1).
When transfer is started, the value of the CSOTn bit of the CSIMn register becomes 1 (transmission
execution status).
Upon transfer completion, the transmission/reception completion interrupt (INTCSIn) is set (1), and the
CSOTn bit is cleared (0). The next data transfer request is then waited for.
Notes 1.
When a data length of 16 bits (CCLn bit of CSIMn register = 1) has been set, read the SIRBn
register. When a data length of 8 bits (CCLn bit of CSIMn register = 0) has been set, read the
SIRBLn register.
2.
When a data length of 16 bits (CCLn bit of CSIMn register = 1) has been set, write to the
SOTBn register. When a data length of 8 bits (CCLn bit of CSIMn register = 0) has been set,
write to the SOTBLn register.
Caution
When the CSOTn bit of the CSIMn register = 1, do not manipulate the CSIn register.