Table of Contents
Advertisement
The Time-Slot Assigner (TSA)
20.2.3 SI RAM
The 512-byte SI RAM contains the SCC and SMC routing information for the TDM
channel. The SI RAM totals 128 32-bit entries—64 entries each for receive and transmit
routing. Representing one time slot, an entry controls from 1 to 16 bits/bytes and up to eight
(four each for Rx and Tx) strobe pins (all active high).
The TDM channel options with their corresponding SI RAM partitioning follow:
• A single TDM channel with static routing—SI RAM is divided into Rx and Tx parts.
• A single TDM channel with dynamic routing—Rx and Tx RAMs are halved.
Note that the SI RAM is uninitialized after power-on—the core should program them
before enabling the TDM channel.
20.2.3.1 Disabling and Reenabling the TSA
The following steps must be taken any time the TSA is disabled. These steps also apply to
changing the SI routing when the TSA is configured for static frames.
1. SCC and SMC connections to the TSA must be disabled.
2. The SI configuration can be modified.
3. SCC and SMC connections to the TSA must be reenabled.
20.2.3.2 TDMa Channel with Static Frames
In an SI configuration using one multiplexed channel with static frames, shown in
Figure 20-4, there are 64 entries in the SI RAM for Rx data/strobe routing and 64 entries
for Tx data/strobe routing.
Figure 20-4. SI RAM Partitioning Using TDMa with Static Frames
20.2.3.3 SI RAM Dynamic Changes
The routing of a TDM channel can be changed while the SCCs and SMCs remain
connected to the TSA. Enabling dynamic changes divides the SI RAM into current-route
and work-space shadow areas.
RDM = 00
One Channel (TDMa) with Independent Rx and Tx Route
SI RAM Address:
0
(32-Bit Entries)
64 Entries
255
256
64 Entries
511
MPC850 Family User's Manual
Framing Signals
L1RCLKa
L1RSYNCa
Rxa
Route
L1TCLKa
L1TSYNCa
Txa
Route
Advertisement
Chapters
Table of Contents
