CHAPTER 18 IEBus CONTROLLER (V850/SC2)
User’s Manual U15109EJ3V0UD
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(d) Slave transmission enable flag (ENSLVTX)...Bit 4
<Set/reset conditions>
Set:
By software
Reset: By software
Cautions 1. Clear the ENSLVTX flag before setting the MSTRQ flag when making a master
request.
If a slave transmission request is sent in slave mode while the ENSLVTX flag is unset,
NACK in the control field will be returned. Moreover, when returning to an enabled
state from a disabled state, transmission becomes valid from the next frame.
2. If the controller receives control data for data/control writing (3H, 7H) while the
ENSLVTX flag is unset, NACK will be returned via the acknowledge bit of the control
field.
3. The status interrupt (INTIE2) will be generated and communication continued when
the control data of a slave status request is returned, even if the ENSLVTX flag is in
the reset status.
(e) Slave reception enable flag (ENSLVRX)...Bit 3
<Set/reset conditions>
Set:
By software
Reset: By software
Caution
If the ENSLVRX flag is reset when the IEBus is busy with other CPU processing, NACK
will be returned via the acknowledge bit of the control field, making it possible to disable
slave reception. Note that resetting this flag only disables individual communication, not
broadcast communication. In individual communication, however, when the received
slave address matches the local address, the start interrupt is generated. If CPU
processing has priority (neither reception nor transmission occurs), be sure to stop the
IEBus unit by resetting the ENIEBUS flag. Note also that when returning to an enabled
state from a disabled state, transmission becomes valid from the next frame.