tmp88cu74 TOSHIBA Semiconductor CORPORATION, tmp88cu74 Datasheet - Page 108

• Manufacturer Part Number: tmp88cu74
• Description: Cmos 8-bit Microcontroller
• Manufacturer: TOSHIBA Semiconductor CORPORATION

SCK
SO1 pin
INTSIO interrupt
SCK
SO1 pin
INTSIO interrupt
SCK
SI1 pin
INTSIO interrupt
(4) Transfer mode
1
1
1
Figure 2.11.7 Number of Bits to Transfer (Example: 4-Bit Serial Transfer)
transmit/receive mode.
pin
pin
pin
a.
SIOM (bits 5 to 3 in SIO1CR) is used to select the transmit, receive, or
4-bit and 8-bit transmit modes
be transmitted first are written to the data buffer registers (DBR). After the data
are written, the transmission is started by setting SIOS to “1”. The data are then
output sequentially to the SO1 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.
will be initiated if the next transmitted data are not loaded to the data buffer
register by the time the number of data words specified with the 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.
register before shifting next data. 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.
Note: Waits are also canceled by writing to a DBR not being used as a transmit data
In these modes, the SIO1CR1 is set to the transmit mode and then the data to
When the internal clock is used, the serial clock will stop and an automatic-wait
When an external clock is used, the data must be written to the data buffer
buffer register; therefore, during SIO do not use such DBR for other
applications.
a
a
a
0
0
0
a
a
a
1
1
1
a
a
a
88CU74-108
2
2
2
a
a
a
3
3
3
(b) 3 words transmit
(a) 1 word transmit
(c) 3 words receive
b
b
0
0
b
b
1
1
b
b
2
2
b
b
3
3
c
c
0
0
c
c
1
1
c
c
2
2
c
c
3
3
TMP88CU74
2007-10-19
2003-02-17