tmp88f846ug TOSHIBA Semiconductor CORPORATION, tmp88f846ug Datasheet - Page 174

• Manufacturer Part Number: tmp88f846ug
• Description: 8 Bit Microcontroller
• Manufacturer: TOSHIBA Semiconductor CORPORATION

16.6 Transfer Mode
16. Synchronous Serial Interface (SIO)
16.6 Transfer Mode
16.6.1 4-bit and 8-bit transfer modes
SIOCR1<SIOM> is used to select the transmit, receive, or transmit/receive mode.
(number of transfer words to be transferred) to the data buffer registers (DBR).
output sequentially to the SO pin in synchronous with the serial clock, starting with the least significant bit
(LSB). As soon as the LSB has been output, the data are transferred from the data buffer register to the shift
register. When the final data bit has been transferred and the data buffer register is empty, an INTSIO (Buffer
empty) interrupt is generated to request the next transmitted data.
transmitted data are not loaded to the data buffer register by the time the number of data words specified with
the SIOCR2<BUF> has been transmitted. Writing even one word of data cancels the automatic-wait; therefore,
when transmitting two or more words, always write the next word before transmission of the previous word is
completed.
Thus, the transfer speed is determined by the maximum delay time from the generation of the interrupt request
to writing of the data to the data buffer register by the interrupt service program.
empty interrupt service program.
SCK pin
SO pin
INTSIO interrupt
SCK pin
SO pin
INTSIO interrupt
SCK pin
SI pin
INTSIO interrupt
In these modes, firstly set the SIO control register to the transmit mode, and then write first transmit data
When the internal clock is used, the serial clock will stop and an automatic-wait will be initiated if the next
Note:Automatic waits are also canceled by writing to a DBR not being used as a transmit data buffer register; there-
When an external clock is used, the data must be written to the data buffer register before shifting next data.
The transmission is ended by clearing SIOCR1<SIOS> to “0” or setting SIOCR1<SIOINH> to “1” in buffer
After the data are written, the transmission is started by setting SIOCR1<SIOS> to “1”. The data are then
Figure 16-6 Number of words to transfer (Example: 1word = 4bit)
fore, during SIO do not use such DBR for other applications. For example, when 3 words are transmitted, do
not use the DBR of the remained 5 words.
a
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3
(b) 3 words transmit
(a) 1 word transmit
(c) 3 words receive
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TMP88F846UG