tmp89fm82t TOSHIBA Semiconductor CORPORATION, tmp89fm82t Datasheet - Page 289

• Manufacturer Part Number: tmp89fm82t
• Description: 8 Bit Microcontroller
• Manufacturer: TOSHIBA Semiconductor CORPORATION

RA000
17.9
17.8.3
17.8.4
Bus Driver Protection
that at which the slave processes the transferred data. More specifically, a write collision error occurs if the slave
transfers a new value to the SEDR register when the master has already started a shift cycle for the next byte.
SESR<WCOL>flag clear to "0". Interrupt pulse will not generated by SESR<WCOL> flag set to "1".
able to keep up with transfer from the master. This occurs when the master shifts out data faster than can be
processed by the slave. The SEI module uses the SESR<SOVF> flag to detect an overflow error.
SESR<SOVF>flag clear to "0". SESR<SOVF> flag is also clared by changing to the master mode. Interrupt pulse
will not generated by SESR<SOVF> flag set to "1".
device which generate a transfer, clear the shift resister to "0" and set the SESR<SSEF>flag. .
SESR<SSEF>flag clear to "0".
・ One method to protect the device against latch-up due to collision of the bus drivers is the use of an open-
・ When using the SEI pins as CMOS outputs, we recommend connecting them to the bus via resistors in order
A write collision error tends to occur on a slave device when the master shifts out data at a speed faster than
The SEDR register read and access to the SEDR resister while SESR<WCOL> flag is set to "1", makes
The transfer bit rate on the SEI bus is determined by the master. At higher bit rates, a slave device may not be
The SOVF flag is set if the following conditions are both met:
When the SOVF flag is set, the SEDR register is overwritten with a new data byte.
The SEDR register read and access to the SEDR resister while SESR<SOVF> flag is set to "1", makes
SS pin input "H" level duriing data transfer exceution causes transfer error for the slave device. The slave
The SEDR register read and access to the SEDR resister while SESR<SSEF> flag is set to "1", makes
Overflow error
Transfer error
drain option. This means changing the SEI pins’ CMOS outputs to the open-drain type, which is accomplished
by setting the SECLK, MOSI, and MISO pins for open-drain individually by using the each Port Input/output
Control Register. In this case, these pins must be provided with pull-up resistors external to the chip.
to protect the device against collision of drivers. However, be sure to select the appropriate resistance value
which will not affect actual device operation (Example: 1 Ω to several kΩ).
Note:Please carefully examine the communication processing routine and communication rate when designing
・ When the SEI module is set as a slave
・ When the previous data byte remains to be read after a new data byte has been received
your application system.
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