NEC Figure 17-5. Serial Bus Interface Control Register Format (1/2), Remarks 1. Bits 0, 1, and 4 (RELT, CMDT, ACKT) are 0 when read after the data is set.

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CHAPTER 17 SERIAL INTERFACE CHANNEL 0 ( µ PD78054Y Subseries)
(3) Serial bus interface control register (SBIC)
This register sets serial bus interface operation and displays statuses.
SBIC is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input sets SBIC to 00H.
Figure 17-5. Serial Bus Interface Control Register Format (1/2)
Note Bits 2, 3, and 6 (RELD, CMDD and ACKD) are read-only bits.
Remarks 1. Bits 0, 1, and 4 (RELT, CMDT, ACKT) are 0 when read after the data is set.
2. CSIE0: Bit 7 of serial operating mode register 0 (CSIM0)
<6> <5> <4> <3> <2> <1> <0><7>
Symbol
SBIC BSYE ACKD ACKE ACKT CMDD RELD CMDT RELT
RELT Used for stop condition signal output.
When RELT = 1, SO0 Iatch is set to 1. After SO0 latch setting, automatically cleared to 0.
Also cleared to 0 when CSIE0 = 0.
R/W
FF61H 00H R/W
Note
Address After Reset R/W
CMDT Used for start condition signal output.
When CMDT = 1, SO0 Iatch is cleared to (0). After SO0 latch clearance, automatically cleared to 0.
Also cleared to 0 when CSIE0 = 0.
R/W
RRELD Stop Condition Detection
Set Conditions (RELD =1)Clear Conditions (RELD = 0)
• When stop condition signal is detected
• When transfer start instruction is executed
• If SIO0 and SVA values do not match in
address reception
• When CSIE0 = 0
• When RESET input is applied
RCMDD Start Condition Detection
Clear Conditions (CMDD = 0)
• When transfer start instruction is executed
• When stop condition signal is detected
• When CSIE0 = 0
• When RESET input is applied
Set Conditions (CMDD = 1)
• When start condition signal is detected
ACKT Used to generate the ACK signal by software when 8-clock wait mode is selected.
Keeps SDA0 (SDA1) low from set instruction (ACKT=1) execution to the next falling edge of SCL.
Also cleared to 0 upon start of serial interface transfer or when CSIE0 = 0.
R/W