American Dynamics PMC-4U-CACI - Manual (Page 17)

Hardware and Software Design • Manufacturing Services
P a g e 17
PMC4U_SCC_IVEC
[0X0C] PMC-4U SCC Interrupt Acknowledge/Vector Read
A read from this address causes the SCC interrupt acknowledge signal to
be asserted. If an interrupt condition exists in the SCC, it will respond by
placing an interrupt vector on the local data bus. This vector is specified by
the user and, depending on the state set in the SCC registers, may contain
status information about the cause of the interrupt.
PMC4U_DIR_TERM
[0X10] PMC-4U Direction and Termination Port read/write
CONTROL DIR_TERM REGISTER
DATA BIT DESCRIPTION
31-20 spare
19-16 TERMination 3-0 1 = terminated
15-3 spare
2-0 DIRection 2-0 0 = read 1 = drive
FIGURE 7 PMC-4U DIRECTION TERMINATION CONTROL BIT MAP
The direction and termination for each of the 16 differential pairs is
controlled through this port. The bits default to ‘0’, which corresponds to
tri-stating the drivers with no termination.
CONTROL CORRESPONDI NG IO BITS
DIR0 IO_0..7
DIR1 IO_8..11
DIR2 IO_12..13
In this design the direction of IO lines 14 and 15 are controlled by the RTS
line of the SCC channel B to allow this signal to control the SCC Tx B
enable.