HD64570 HITACHI [Hitachi Semiconductor], HD64570 Datasheet - Page 156

• Manufacturer Part Number: HD64570
• Description: Serial Communications Adaptor
• Manufacturer: HITACHI [Hitachi Semiconductor]

Bit 7 (EOM: Receive End of Message): Indicates whether or not a receive frame has ended in
bit synchronous mode. This bit is cleared when 1 is written to this bit position.
Rev. 0, 07/98, page 140 of 453
Async
Byte sync
Bit sync HDLC
Read/Write
Initial value
Receive end of message
• Bit synchronous mode
0:
1:
Note: The bits marked with * are reserved. These bits always read 0 and can be set to 0 or 1.
Asynchronous/Byte synchronous mode
Reserved. This bit always reads 0 and can be set to 0 or 1.
Bit synchronous mode
The EOM bit indicates whether or not a receive frame has ended. When the CRCCC bit of
mode register 0 (MD0) is 1, the EOM bit is set to 1 by the last character in the I field of the
receive frame. When the CRCCC bit of MD0 is 0, the EOM bit is set to 1 by the last character
of FCS. Also, when the receive frame end status indicates either a short frame, residual bit
frame, or abort, the EOM bit is set to 1.
Receive frame end
not detected
Receive frame end
detected
Parity/MP bit
• Asynchronous mode
0:
1:
Short frame
• Bit synchronous mode
0:
1:
Parity/MP bit = 0
Parity/MP bit = 1
Normal end of frame
Short frame detected
R/W
EOM
—
7
0
*
SHRT
R/W
PMP
—
6
0
*
R/W
ABT
PE
—
5
0
Parity error
• Asynchronous mode
0: No parity error detected
1: Parity error detected
Abort end frame
• Bit synchronous mode
0: Normal end of frame
1: Frame with abort end detected
Framing error
• Asynchronous mode
0:
1:
*
Residual bit frame
•
0:
1:
Bit synchronous
mode
No framing error
detected
Framing error
detected
Normal end of
frame
Residual bit frame
detected
FRME
R/W
RBIT
—
4
0
*
OVRN
R/W
3
0
CRCE
R/W
—
2
0
Overrun error
0: No overrun error detected
1: Overrun error detected
*
—
—
1
0
CRC error
• Byte/Bit synchronous mode
0: No CRC error detected
1: CRC error detected
*
—
—
0
0
*