CHAPTER 10 SERIAL INTERFACE FUNCTION
User’s Manual U13850EJ4V0UM
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10.2.1 Configuration
CSIn includes the following hardware.
Table 10-1. Configuration of CSIn
Item
Configuration
Registers
Serial I/O shift registers 0 to 3 (SIO0 to SIO3)
Control registers
Serial operation mode registers 0 to 3 (CSIM0 to CSIM3)
Serial clock selection registers 0 to 3 (CSIS0 to CSIS3)
Figure 10-1. Block Diagram of 3-Wire Serial I/O
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 to 3
2.
TMx output is as follows:
When n = 0 or 3: TM2
When n = 1 or 2: TM3
(1) Serial I/O shift registers 0 to 3 (SIO0 to SIO3)
SIOn is an 8-bit register that performs parallel-serial conversion and serial transmit/receive (shift operations)
synchronized with the serial clock.
SIOn is set by an 8-bit memory manipulation instruction.
When “1” is set to bit 7 (CSIEn) of serial operation mode register n (CSIMn), 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 clears these registers to 00H.
Caution Do not execute SIOn accesses except for the accesses that become transfer start trigger
during transfer operation (read is disabled when MODE = 0 and write is disabled when MODE
= 1).