Freescale Semiconductor PowerQUICC MPC885 Reference Manual page 631

Bits Name
0 CRORa Address of the current route of TDMa receiver
0 Address 0–127 when SIGMR[RDM] = 01
Address 0–63 when SIGMR[RDM] = 11
1 Address 128–255 when SIGMR[RDM] = 01
Address 64–127 when SIGMR[RDM] = 11
1 CROTa Address of the current route of TDMa transmitter
0 Address 256–383 when SIGMR[RDM] = 01
Address 256–319 when SIGMR[RDM] = 11
1 Address 384–511 when SIGMR[RDM] = 01
Address 320–383 when SIGMR[RDM] = 11
2 CRORb Address of the current route of TDMb receiver—only valid when SIGMR[RDM] = 11
0 Address 128–191
1 Address 192–255
3 CROTb Address of the current route of TDMb transmitter—only valid when SIGMR[RDM] = 11
0 Address 384–447
1 Address 448–511
4–7 — Reserved, should be cleared.
20.2.4.6 SI RAM Pointer Register (SIRP)
The SI RAM pointer (SIRP) register, shown in
serviced. SIRP gives the real-time status location of the SI inside a TDM frame—useful for debugging and
synchronizing system activity with the TDMs' activity. However, simply reading the status register SISTR
is sufficient for most applications.
The user can determine which RAM entry in the SI RAM is in progress, but cannot determine the status
within that entry. For example, if the SIRP indicates an SI RAM entry is active, but the entry is
programmed to select four contiguous 8-bit time slots of a TDM, it cannot be determined which of the four
time slots is in progress. However, SIRP updates the status as soon as the next SI RAM entry begins
processing. The value of SIRP changes on serial clock transitions. Before acting on the information in this
register, perform two reads to verify the same value is returned.
One of the four strobes can be connected externally to an interrupt pin to generate an interrupt on a
particular SI RAM entry to start or stop TSA execution.
The pointers in SIRP indicate the SI RAM entry word offset that is in progress.
Freescale Semiconductor
Table 20-8. SISTR Field Descriptions
Figure
MPC885 PowerQUICC Family Reference Manual, Rev. 2
Description
20-23, indicates the RAM entry currently being
Serial Interface
20-25