Register To Control Serial Interface (Sio31) - NEC mPD780065 Series Preliminary User's Manual

16.3 Register to Control Serial Interface (SIO31)

The serial interface (SIO31) uses the following type of register to control functions.
• Serial operation mode register 31 (CSIM31)
(1) Serial operation mode register 31 (CSIM31)
This register is used to enable or disable SIO31's serial clock, operation modes, and specific operations.
CSIM31 can be set by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets CSIM31 to 00H.
Caution In 3-wire serial I/O mode, set the port mode register (PMXX) as follows. In each case, set the output
latch to 0.
• During serial clock output (master transmission or master reception)
Set P90 (SCK31) to output mode (PM90 = 0)
• During serial clock input (slave transmission or slave reception)
Set P90 to input mode (PM90 = 1)
• During transmit/transmit and receive mode
Set P91 (SO31) to output mode (PM91 = 0)
• During receive mode
Set P92 (SI31) to input mode (PM92 = 1)
Figure 16-2. Format of Serial Operation Mode Register 31 (CSIM31)
Address: FFB1H After reset: 00H
Symbol 7
CSIM31 CSIE31
CSIE31
0
1
MODE1
0
1
SCL311
0
0
1
1
CHAPTER 16 SERIAL INTERFACE (SIO31)
R/W
6 5
0 0
Enable/disable specification for SIO31
Shift register operation
Operation stop Clear
Operation enable Count operation enable
Transfer operation modes and flags
Operation mode
Transmit/transmit and receive mode Write to SIO31
Receive-only mode Read from SIO31
SCL310
0 External clock input to SCK31
3
1 f /2 (1.05 MHz)
X
4
0 f /2 (524 kHz)
X
5
1 f /2 (262 kHz)
X
Preliminary User's Manual U13420EJ2V0UM00
4 3 2
0 0 MODE1
Serial counter
Port function
Serial function + port function
Transfer start trigger
Normal output
Fixed at low level
Clock selection
1 0
SCL311 SCL310
Port
Note 1
Note 2
SO31 output
259