![NEC V850/SC1 User Manual Download Page 543](http://html.mh-extra.com/html/nec/v850-sc1/v850-sc1_user-manual_248178543.webp)
CHAPTER 18 IEBus CONTROLLER (V850/SC2)
User’s Manual U15109EJ3V0UD
541
(10) IEBus slave status register (SSR)
This register indicates the communication status of the slave unit. After receiving a slave status transmission
request from the master, the CPU reads this register, and writes a slave status to the IEBus data register (DR)
to transmit the slave status. At this time, because the telegraph length is automatically set to “01H”, setting of
the IEBus telegraph length register (DLR) is not required (because it is preset by hardware).
Bits 6 and 7 indicate the highest mode supported by the unit, and are fixed to “01” (mode 1).
After reset: 41H
R
Address: FFFFF3F2H
7
6
5
<4>
3
<2>
<1>
<0>
SSR
0
1
0
STATSLV
0
STATLOCK
STATRX
STATTX
STATSLV
Slave transmission status flag
0
Slave transmission stops
1
Slave transmission enabled
STATLOCK
Lock status flag
0
Unlock status
1
Lock status
STATRX
DR receive status
0
Receiving data not stored in DR
1
Receiving data stored in DR
STATTX
DR transmit status
0
Transmission data not stored in DR
1
Transmission data stored in DR
(a) Slave transmission status flag (STATSLV)...Bit 4
This flag reflects the contents of the slave transmission enable flag.
(b) Lock status flag (STATLOCK)...Bit 2
This flag reflects the contents of the locked flag.
(c) DR reception status (STATRX)...Bit 1
This flag indicates the DR reception state.
(d) DR transmission status (STATTX)...Bit 0
This flag indicates the DR transmission state.