UPD78F0537DGA(T)-9EV-A NEC, UPD78F0537DGA(T)-9EV-A Datasheet - Page 448

• Manufacturer Part Number: UPD78F0537DGA(T)-9EV-A
• Description: 8BIT MCU, 128K FLASH, 7KB RAM, SMD
• Manufacturer: NEC

Specifications of UPD78F0537DGA(T)-9EV-A

• Controller Family/series: UPD78
• No. Of I/o's: 55
• Ram Memory Size: 7KB
• Cpu Speed: 20MHz
• No. Of Timers: 8
• No. Of Pwm: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 128KB
• Oscillator Type: External, Internal

448
(2) When communication reservation function is disabled (bit 0 (IICRSV) of IIC flag register 0 (IICF0) = 1)
(Communication reservation)
Note The communication reservation operation executes a write to IIC shift register 0 (IIC0) when a stop
Remark
When bit 1 (STT0) of IIC control register 0 (IICC0) is set to 1 when the bus is not used in a communication
during bus communication, this request is rejected and a start condition is not generated. The following two
statuses are included in the status where bus is not used.
• When arbitration results in neither master nor slave operation
• When an extension code is received and slave operation is disabled (ACK is not returned and the bus was
To confirm whether the start condition was generated or request was rejected, check STCF (bit 7 of IICF0).
The time shown in Table 17-7 is required until STCF is set to 1 after setting STT0 = 1. Therefore, secure the
time by software.
released when bit 6 (LREL0) of IICC0 was set to 1)
condition interrupt request occurs.
STT0:
MSTS0: Bit 7 of IIC status register 0 (IICS0)
IIC0:
Bit 1 of IIC control register 0 (IICC0)
IIC shift register 0
Yes
Note
Figure 17-22. Communication Reservation Protocol
Cancel communication
reservation
Define communication
reservation
CHAPTER 17 SERIAL INTERFACE IIC0
MOV IIC0, #××H
MSTS0 = 0?
SET1 STT0
Wait
DI
EI
User’s Manual U17260EJ6V0UD
(Generate start condition)
No
Sets STT0 flag (communication reservation)
Defines that communication reservation is in effect
(defines and sets user flag to any part of RAM)
Secures wait period set by software (see Table 18-6).
Confirmation of communication reservation
Clear user flag
IIC0 write operation