Freescale Semiconductor PowerQUICC MPC885 Reference Manual page 827

Powerquicc family

Table of Contents

SMC GCI C/I Channel Reception Process

The SMC receiver continuously monitors the C/I channel. When it recognizes a change in the data and this

value is received in two successive frames, it is interpreted as valid data. This is called the double last-look

method. The CP stores the received data byte in the C/I RxBD and a maskable interrupt is generated. If the

SMC is configured to support SCIT channel 1, the double last-look method is not used.

SMC GCI Commands

The commands in

Initializes transmit and receive parameters in the parameter RAM to their reset state.

INIT TX AND RX

This receiver command can be issued when the MPC885 implements the monitor channel protocol.

TRANSMIT ABORT

When it is issued, the MPC885 sends an abort request on the A bit.

This transmitter command can be issued when the MPC885 implements the monitor channel

protocol. It is usually issued because the device is not responding or A bit errors are detected. The

MPC885 sends an abort request on the E bit at the time this command is issued.

SMC GCI Monitor Channel RxBD

The GCI monitor channel RxBD, shown in

channel receive byte. The RxBD itself receives the monitor data.

describes SMC monitor channel RxBD fields.

Table 29-19. SMC Monitor Channel RxBD Field Descriptions

0 The CP clears E when the byte associated with this BD is available to the core.

1 The core sets E when the byte associated with this BD has been read.

Last (EOM). Set when the EOM indication is received on the E bit. Note that when this bit is set, the

data byte is invalid.

Error condition. Set when an error occurs on the monitor channel protocol. The error condition

indicates that a new byte was sent before the SMC acknowledged the previous byte.

Data mismatch. Set when two different consecutive bytes are received; cleared when the last two

consecutive bytes match. The SMC waits for the reception of two identical consecutive bytes before

writing new data to the RxBD.

Freescale Semiconductor

are issued to CPCR.

Table 29-18. SMC GCI Commands

Figure 29-16. SMC GCI Monitor Channel RxBD

MPC885 PowerQUICC Family Reference Manual, Rev. 2

Serial Management Controllers (SMCs)

29-16, is used by the CP to report on the monitor