Connect Tech - Xtreme/Multi-I/O - Users Guide
Document: CTIM-00116
Revision: 0.02
0.02
Page 33 of 50
Connect Tech Inc. Proprietary Information
Date: Apr. 14, 2015
Command, Control, Status Registers
These registers provide the complete control and operation of the J1708 port.
Register Name
IO
Address
Offset
MEM
Address
Offset
Access Comments
Command
0x00
0x00
R/W(1)
Control
0x01
0x04
R/W
TX Priority
0x02
0x08
R/W
TX Problem Limit
0x03
0x0C
R/W
J1708 Interrupt Status
0x04
0x10
R/W(1)
FIFO Status
0x05
0x14
RO
RX EOM Level
0x06
0x18
R/W
RX Afull Level
0x07
0x1C
R/W
User-Ta
0x08
0x20
R/W
R/W
Read or Write, unused bits are ignored on write, and return zero’s on read.
RO
Read only, unused bits return zero’s
R/W(1)
Read or Write, Writing a zero (0) has no effect. Unused bits are ignored on write, and return
zero’s on read.
Command Register (Offset: 0x00)
This register is setup so that it’s control bits operate independently. Only when a one (1) is written to the
appropriate bit, does the indicated action take place. Writing a zero(0) to a bit has NO effect. All bits in this
register will self-clear when the operation takes place.
Control Item
Bit
Offset
Bit
Value
Comment(s)
Restart J1708 Bus SYNC
0
0x1
Bit clears when the Receiver enters the SYNC state
Abort TX
1
0x2
Bit clears when Abort is completed
TX Kick
2
0x4
Force the generation of the
TX FIFO Empty
interrupt
Unused
3
31
Not used
Restart J1708 Bus SYNC
This bit will restart the J1708 Bus re-synchroniation process. See the above
Operation
section for details.
Abort TX
This bit causes the Transmitter to abort sending bytes as soon as the current byte has been completely sent. The
Transmitter FIFO is also flushed (emptied) by this command.
TX Kick
This bit causes the
TX FIFO Empty
interrupt to occur, but
only
if the TX FIFO is actually empty at the time
when the TX Kick command is issued. If the TX FIFO is not empty, then this command is ignored, and the TX
FIFO Empty interrupt will occur when the TX FIFO gets to the empty point (or some other TX event occurs,
which terminates the transmission).
