MPC823 datasheet(69/74 Pages) MOTOROLA

69 / 74 page

Communication Processor Module

MOTOROLA

MPC823 REFERENCE MANUAL

16-447

W—Wrap (Final Buffer Descriptor in Table)

0 = This is not the last buffer descriptor in the TX buffer descriptor table.

1 = This is the last buffer descriptor in the TX buffer descriptor table. After this buffer is

used, the communication processor module receives incoming data into the first

buffer descriptor that TBASE points to in the table. The number of TX buffer

descriptors in this table is programmable and determined only by the W bit and

overall space constraints of the dual-port RAM.

I—Interrupt

0 = No interrupt is generated after this buffer is serviced.

1 = The TXB or TXE bit in the SPI event register is set when this buffer is serviced. TXB

and TXE can cause interrupts if they are enabled.

L—Last

0 = This buffer does not contain the last character of the message.

1 = This buffer contains the last character of the message.

CM—Continuous Mode

This bit is only valid when the serial peripheral interface is in master mode. In slave mode,

it must be written as a zero.

0 = Normal operation.

1 = The R bit is not cleared by the communication processor module after this buffer

descriptor is closed, thus allowing the associated data buffer to be automatically

retransmitted next time the communication processor module accesses this buffer

descriptor.

UN—Underrun

This bit indicates that the serial peripheral interface has encountered a transmitter underrun

condition while transmitting a data buffer. This error condition is only valid when the serial

peripheral interface is in slave mode. The serial peripheral interface writes this bit after it

finishes transmitting the associated data buffer.

ME—Multimaster Error

This bit indicates that this buffer is closed because the SPISEL pin was asserted when the

serial peripheral interface was in master mode. This indicates a synchronization problem

between multiple masters on the SPI bus. The serial peripheral interface writes this bit after

it finishes transmitting the associated data buffer.

MPC823 bảng dữ liệu(PDF) 69 Page - Motorola, Inc