
Serial Interface with Time Slot Assigner
7-88
MC68360 USER’S MANUAL
CROTa—Current Route of TDMa Transmitter
0 = The current-route transmitter RAM is in address:
128–191 when the SI supports one TDM (RDM = 01).
128–159 when the SI supports two TDMs (RDM = 11).
1 = The current-route transmitter RAM is in address:
192–255 when the SI supports one TDM (RDM = 01).
160–191 when the SI supports two TDMs (RDM = 11).
CRORb—Current Route of TDMb Receiver
This bit is valid only in the RAM division mode (RDM bits in the SIGMR equal 11).
0 = The current-route receiver RAM is in address 64–95.
1 = The current-route receiver RAM is in address 96–127.
CROTb—Current Route of TDMb Transmitter
This bit is valid only in the RAM division mode (RDM bits in the SIGMR equal 11).
0 = The current-route transmitter RAM is in address 192–223.
1 = The current-route transmitter RAM is in address 224–255.
Bits 3–0—Reserved
7.8.5.6 SI RAM POINTERS (SIRP). This 32-bit, read-only register indicates to the user
which RAM entry is currently being serviced. This gives a real-time status of where the SI
current is inside the TDM frame.
Although SIRP does not need to be accessed by most users, it does provide information that
may be helpful for debugging and synchronization of some system activity to the activity on
the TDMs. Reading SISTR should be sufficient for most applications.
The user can determine which RAM entry in the SI RAM is currently in progress, but cannot
determine the status within that entry. For instance, if the RAM entry is programmed to
select four contiguous time slots from the TDM and the SIRP indicates the entry is currently
active, the user does not know which of the four time slots is currently in progress. The SIRP
will, however, change its status immediately when the next SI RAM entry begins to be pro-
cessed.
NOTE
The user may also connect one of the four strobes externally to
an interrupt pin to generate an interrupt on a particular SI RAM
entry starting or ending execution by the TSA.
The value of this register is changed upon transitions of the serial clocks. Before acting on
the information in this register, the user should perform two reads and verify that the two
reads returned the same value.
F
re
e
sc
a
le
S
e
m
ic
o
n
d
u
c
to
r,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
n
c
..
.