CHAPTER 11 SERIAL INTERFACE FUNCTION
User’s Manual U15109EJ3V0UD
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11.2.1 Configuration
CSIn includes the following hardware.
Table 11-1. Configuration of CSIn
Item
Configuration
Registers
Serial I/O shift register n (SIOn)
Serial operation mode register n (CSIMn)
Control registers
Serial clock select register n (CSISn)
Remark
n = 0, 2, 3
Figure 11-1. Block Diagram of 3-Wire Serial I/O (CSI0, CSI2, CSI3)
TMx output
Clock selection
SCKn
SOn
SIn
INTCSIn
Internal bus
Selector
8
Serial clock controller
Serial clock
counter
Serial I/O shift
register n (SIOn)
Interrupt
generator
Remarks
1.
n = 0, 2, 3
2.
TMx output is as shown below.
When n = 0, 3: TM5 output
When n = 2:
TM6 output
(1) Serial I/O shift register n (SIOn)
SIOn is an 8-bit register that performs parallel-serial conversion and serial transmission/reception (shift
operations) in synchronization with the serial clock.
SIOn is set by an 8-bit memory manipulation instruction.
When bit 7 (CSIEn) of serial operation mode register n (CSIMn) is set to 1, a serial operation can be started by
writing data to or reading data from SIOn.
When transmitting, data written to SIOn is output via the serial output (SOn).
When receiving, data is read from the serial input (SIn) and written to SIOn.
RESET input sets these registers to 00H.
Caution
Do not access SIOn except by the transfer start trigger during a transfer operation (read is
disabled when MODEn = 0 and write is disabled when MODEn = 1).
Remark
n = 0, 2, 3