3-Wire Serial I/O Mode With Automatic Transmit/Receive Function - NEC 78K0 User Manual

17.4.3 3-wire serial I/O mode with automatic transmit/receive function

Up to 32 bytes of data can be transmitted/received without using software in the mode in which bit 6 (ATE0) of
serial operation mode specification register 0 (CSIMA0) is set to 1. After communication is started, only data of the
set number of bytes stored in RAM in advance can be transmitted, and only data of the set number of bytes can be
received and stored in RAM.
In addition, to transmit/receive data continuously, handshake signals (STB0 and BUSY0) generated by hardware
are supported. Therefore, connection to peripheral LSIs such as OSD (On Screen Display) LSIs and LCD
controller/drivers can be easily realized.
(1) Registers used
• Serial operation mode specification register 0 (CSIMA0)
• Serial status register 0 (CSIS0)
• Serial trigger register 0 (CSIT0)
• Divisor selection register 0 (BRGCA0)
• Automatic data transfer address point specification register 0 (ADTP0)
• Automatic data transfer interval specification register 0 (ADTI0)
• Port mode register 14 (PM14)
• Port register 14 (P14)
The relationship between the register settings and pins is shown below.
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CHAPTER 17 SERIAL INTERFACE CSIA0
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User's Manual U15947EJ2V0UD