NEC uPD78P078 - Manual (Page 396)

396
CHAPTER 18 SERIAL INTERFACE CHANNEL 0 (
µ
PD78078Y Subseries)
<6> <5> <4> <3> <2> <1> <0> <7>
Symbol
SBIC BSYE ACKD ACKE FF61H 00H R/W Note1
Address After Reset R/W
ACKT CMDD RELD CMDT RELT
(b) Serial bus interface control register (SBIC)
SBIC is set by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets SBIC to 00H.
R/W RELT Use for stop condition output. When RELT = 1, SO0 latch is set to 1. After SO0 latch setting, automatically cleared to
0. Also cleared to 0 when CSIE0 = 0.
R/W CMDT Use for start condition output. When CMDT = 1, SO0 latch is cleared to 0. After clearing SO0 latch, automatically
cleared to 0. Also cleared to 0 when CSIE0 = 0.
R RELD Stop Condition Detection
0 Clear Conditions
• 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
1 Setting Condition
• When stop condition is detected
R CMDD Start Condition Detection
0 Clear Conditions
• When transfer start instruction is executed
• When stop condition is detected
• When CSIE0 = 0
• When RESET input is applied
1 Setting Condition
• When start condition is detected
R/W ACKT SDA0 (SDA1) is set to low after the Set instruction execution (ACKT = 1) before the next SCL falling edge. Used for
generating an ACK signal by software if the 8-clock wait mode is selected. Cleared to 0 if CSIE = 0 when a transfer by
the serial interface is started.
R/W ACKE Acknowledge Signal Automatic Output Control Note 2
0 Disabled (with ACKT enabled). Used when receiving data in the 8-clock wait mode or when transmitting data. Note 3
1 Enabled.
After completion of transfer, acknowledge signal is output in synchronization with the 9th falling edge of SCL clock
(automatically output when ACKE = 1). However, not automatically cleared to 0 after acknowledge signal output.
Used for reception when the 9-clock wait mode is selected.
R ACKD Acknowledge Detection
0 Clear Conditions
• When transfer start instruction is executed
• When CSIE0 = 0
• When RESET input is applied
1 Set Conditions
• When acknowledge signal is detected at the rising edge of SCL clock after completion of transfer
R/W BSYE Control of N-ch Open-Drain Output for Transmission in I 2 C Bus Mode Note 5
Note 4
0 Output enabled (transmission)
1 Output disabled (reception)
Notes 1. Bits 2, 3, and 6 (RELD, CMDD, ACKD) are read-only bits.
2. This setting must be performed prior to transfer start.
3. In the 8-clock wait mode, use ACKT for output of the acknowledge signal after normal data reception.
4. The busy mode can be released by the start of a serial interface transfer or reception of an address
signal. However, the BSYE flag is not cleared.
5. When using the wake-up function, set BSYE to 1.
Remark CSIE0 : Bit 7 of serial operating mode register 0 (CSIM0)