Motorola MPC8260 - Manual (Page 755)

MOTOROLA Chapter 27. Multi-Channel Controllers (MCCs) 27-25
Part IV. Communications Processor Module
27.12.1 Single-Channel Initialization
The following sequence must be followed to initialize and start a single channel (after reset
or after a fatal error):
1. Program the SI. The entries the MCC channels uses must point to the null channel
(set in the SI RAM entry MCC = 0, CSEL = 0 and the correct size - 1 byte); entries
used by other controllers (not MCC) can be activated at this time.
2. Initialize the MCC parameters (in DPR and external memory).
3. Enable the MCC channel as described in Section 27.6.1, ÒInternal Transmitter State
(TSTATE),Ó and Section 27.6.4, ÒInternal Receiver State (RSTATE).Ó
4. Reprogram the SI RAM to point to the enabled channel(s).
The following sequence must be followed to stop a single channel in order to change the SI
without using the shadow SI:
1. Issue a STOP command for the respective channel as described in Section 27.9,
ÒMCC Commands.Ó
2. Change the SI.
3. Enable the MCC channel(s) as described in Section 27.6.1, ÒInternal Transmitter
State (TSTATE),Ó and Section 27.6.4, ÒInternal Receiver State (RSTATE).Ó
It is possible to change the SI using the SI shadow while the channel is active. Both the
primary and the shadow conÞguration of the SI RAM must observe the conÞguration
deÞned in MCCF (see Section 27.8, ÒMCC ConÞguration Registers (MCCFx)Ó). The
MCCF cannot be changed while there are active channels.
The following sequence must be followed to stop a single channel in order to change the
MCC parameters of the respective channel:
1. Issue a STOP command for the respective channel as described in Section 27.9,
ÒMCC Commands,Ó or change the associated SI RAM entry to point to a channel
which is not active and wait for two frame periods in order to clear the internal
FIFOs.
2. Change the channel parameters.
3. Enable the MCC channel(s) as described in Section 27.6.1, ÒInternal Transmitter
State (TSTATE),Ó and Section 27.6.4, ÒInternal Receiver State (RSTATE),Ó or
change the associated SI RAM entry to point to the respective channel.