Motorola MPC8260 User Manual

Page of 1006
26-30
MPC8260 PowerQUICC II UserÕs Manual
MOTOROLA
Part IV.  Communications Processor Module
26.5  The SMC in GCI Mode
The SMC can control the C/I and monitor channels of the GCI frame. When using the SCIT
conÞguration of a GCI, one SMC can handle SCIT channel 0 and the other can handle SCIT
channel 1. The main features of the SMC in GCI mode are as follows:
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Each SMC channel supports the C/I and monitor channels of the GCI (IOM-2) in 
ISDN applications
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Two SMCs support both sets of C/I and monitor channels in SCIT channels 0 and 1
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Full-duplex operation
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Local loopback and echo capability for testing
To use the SMC GCI channels properly, the TSA must be conÞgured to route the monitor
and C/I channels to the preferred SMC. Chapter 14, ÒSerial Interface with Time-Slot
Assigner,
Ó describes how to program this conÞguration. GCI mode is selected by setting
SMCMR[SM] to 0b10. Section 26.2.1, ÒSMC Mode Registers (SMCMR1/SMCMR2)Ó
describes other protocol-speciÞc SMCMR bits. 
26.5.1  SMC GCI Parameter RAM
The GCI parameter RAM differs from that for UART and transparent mode. The CP
accesses each SMCÕs GCI parameter table using a user-programmed pointer
(SMCx_BASE) located in the parameter RAM; see Section 13.5.2, ÒParameter RAM.Ó
Each SMC GCI parameter RAM table can be placed at any 64-byte aligned address in the
dual-port RAMÕs general-purpose area (banks #1Ð#8). In GCI mode, parameter RAM
contains the BDs instead of pointers to them. Compare Table 26-17 with Table 26-2 to see
the differences. (In GCI mode, the SMC has no extra protocol-speciÞc parameter RAM.)
Table 26-17. SMC GCI Parameter RAM Memory Map 
Offset 
1
1
From the pointer value programmed in SMCx_BASE: SMC1_BASE at 0x87FC, SMC2_BASE at 0x88FC.
Name
Width
Description
0x00
M_RxBD
Half word
0x02
M_TxBD
Half word
0x04
CI_RxBD
Half word
0x06
CI_TxBD
Half word
0x08
RSTATE
2
2
RSTATE, M_RxD, M_TxD, CI_RxD, and CI_TxD do not need to be accessed by the user in normal operation, 
and are reserved for RISC use only.
Word
Rx/Tx Internal State
0x0C
Half word
Monitor Rx Data
0x0E
Half word
Monitor Tx Data
0x10
CI_RxD 
Half word
C/I Rx Data
0x12
CI_TxD 
Half word
C/I Tx Data