STANDARD PRODUCT
PM4351 COMET
DATA SHEET
PMC-1970624
ISSUE 10
COMBINED E1/T1 TRANSCEIVER
PROPRIETARY AND CONFIDENTIAL
421
14.9 Using the Per-Channel Serial Controllers
14.9.1 Initialization
Before the TPSC (RPSC) block can be used, a proper initialization of the internal
registers must be performed to eliminate erroneous control data from being
produced on the block outputs. The output control streams should be disabled
by setting the PCCE bit in the TPSC (RPSC) Configuration Register to logic 0.
Then, all 96 locations of the TPSC (RPSC) must be filled with valid data.
Finally, the output streams can be enabled by setting the PCCE bit in the TPSC
(RPSC) Configuration Register to logic 1.
14.9.2 Direct Access Mode
Direct access mode to the TPSC or RPSC is not used in the COMET. However,
direct access mode is selected by default whenever the COMET is reset. The
IND bit within the TPSC and RPSC Configuration Registers must be set to
logic 1 after a reset is applied.
14.9.3 Indirect Access Mode
Indirect access mode is selected by setting the IND bit in the TPSC or RPSC
Configuration Register to logic 1. When using the indirect access mode, the
status of the BUSY indication bit should be polled to determine the status of the
microprocessor access: when the BUSY bit is logic 1, the TPSC or RPSC is
processing an access request; when the BUSY bit is logic 0, the TPSC or RPSC
has completed the request.
The indirect write programming sequence for the TPSC (RPSC) is as follows:
1. Check that the BUSY bit in the TPSC (RPSC) μP Access Status Register is
logic 0.
2. Write the channel data to the TPSC (RPSC) Channel Indirect Data Buffer
register.
3. Write RWB=0 and the channel address to the TPSC (RPSC) Channel Indirect
Address/Control Register.
4. Poll the BUSY bit until it goes to logic 0. The BUSY bit will go to logic 1
immediately after step 3 and remain at logic 1 until the request is complete.
5. If there is more data to be written, go back to step 1.