HD64570 Datasheet, PDF (25/469 Pages) Hitachi Semiconductor – Serial Communications Adaptor

1.5.2 Byte-Synchronous Mode
Item
Character length
Error control
Synchronous characters
External synchronization
Synchronization
Underrun
Idle
Error detection
Description
8 bits
Generates and checks CRC codes (CRC-16, CRC-CCITT)
1 or 2 characters
Supported
Can transmit, detect and delete SYN character
Idle, or CRC + idle output
Mark or SYN character output
CRC error, overrun error, underrun error
1.5.3 Bit-Synchronous Mode
Item
Character length
Error control
Bit pattern
Frame subdivision
Address field
End of frame
Data input/output
Residual bits
Short frame
Underrun
Idle
Description
8 bits
Generates and checks CRC codes (CRC-16, CRC-CCITT)
Detects and generates flag, abort, and idle
Detects subdivision flag (single flag) between frames
Four address field checks (can recognize group addresses
and global addresses)
When EOM is received
Zero insert/delete
Detects residual bit frames
Detects short (invalid) frames
Abort + idle, or FCS + flag + idle
Mark or flag
Rev. 0, 07/98, page 9 of 453