Zilog Z16C30 - Manual (Page 181)

8-26
Z16C30 USC ®
U SER ' S M ANUAL Z ILOG
UM97USC0100
14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 15
Rcmd (WO)
Receive Command/Status Register (RCSR) Register Address 1 0 b 10010
Bit(s)
Field/Bit
Name
Conditions
/Context
Description
RW
Status
Ref Chapter: Section
ShortF/
CVType
RCSR15-12
2ndBE 1stBE
RxResidue
Exited
Hunt
Idle
Rcved
Break
/Abort Rx
Bound
CRCE
/FE
Abort
/PE
Rx
Over
Rx
Avail
RCmd Sync 0000=no operation; 0001=Reserved;
0010=Clear Receive CRC Generator;
0011=Enter Hunt Mode; 0100=Reserved;
0101=Select RICRHi=RxFIFO Status;
0110=Select RICRHi=/INT Level;
0111=Select RICRHi=/RxREQ Level;
1xxx=Reserved WO 5: Commands
RCSR15 2ndBE Last RDR
read was
16 bits 1=2nd-oldest byte in RxFIFO had RxBound,
PE, or RxOver when RDR was last read RO 5: Status Reporting:
Detailed Status in the RCSR
RCSR14 1stBE 1=oldest byte in RxFIFO had RxBound,
PE, or RxOver when RDR was last read RO
RCSR11-19 RxResidue 000=frame ended at character boundary;
001-111=number of extra bits at end RO 5: HDLC/SDLC Mode:
Frame Length Residuals H/SDLC
RCSR8 ShortF/
CVType H/SDLC,
CMR7-4
not xx00 1=received frame ended before
Address/Control fields (see Note 1) R,W1U
or RO
5: Status Reporting:
Detailed Status in the RCSR
0=received Data word;
1=received Command/Status word (see Note 1) ACV
(1553B)
RCSR7 ExitedHunt 1=receiver has left Hunt mode R,W1U
RCSR6 IdleRcved 1=15 or 16 ones received R,W1U
RCSR5 Break/Abort 1=Break received R,W1U
H/SDLC
Async
1=Abort received
RCSR4 RxBound 1=address character (see Note 2) R,W1C
or RO
ACV
(1553B)
Nine Bit
1=2nd (or only) byte of word (see Note 2)
Ext Sync,
T. Bisync 1=end of message (see Note 2)
1=end of frame (see Note 2) HDLC/
SDLC
802.3
RCSR3 CRCE/FE 1=CRC not correct (at this point; see Note 1) RO
Async
Sync
1=framing error (Stop bit = zero/space;
see Note 1)
RCSR2 Abort/PE 1=parity error (see Note 2) R,W1C
or RO
RCSR1 RxOver 1=RxFIFO overflow (see Note 2) R,W1C
RO??
RCSR0 RxAvail 1=RxFIFO is not empty RO
Note 1: The USC carries these bits through the RxFIFO with data characters; they may represent the status of the oldest character or two
currently in the FIFO, or of the last one or two read from it, as described in the referenced Chapter/Section.
Note 2: The USC carries these bits through the RxFIFO with data characters; they may represent the status of the oldest character or two
currently in the FIFO, of the last one or two read from it, or may be a cumulative/latched bit, as described in the referenced Chapter/Section.
QAbort
(RMR8)=0
H/SDLC,
QAbort=1 1=Abort followed this character (see Note 2)
RW = Read/Write, RO = Read Only, WO = Write Only – for other codes see p. 8-10.
UM009402-0201