MPC823 datasheet(4/74 Pages) MOTOROLA

4 / 74 page

Communication Processor Module

16-382

MPC823 REFERENCE MANUAL

MOTOROLA

In UART and Transparent modes, the serial management controllers have a memory

structure that is similar to the serial communication controllers. Each buffer is referenced by

a buffer descriptor and organized in a buffer descriptor ring located in the dual-port RAM, as

illustrated in Figure 16-114.

The buffer descriptor ring allows you to define buffers for transmission and reception and

each ring forms a circular queue. Using the buffer descriptors, the communication processor

module confirms reception and transmission so that the microprocessor knows the buffers

have been serviced. The data buffers can reside in external or internal memory and the data

buffers reside in the parameter area of an SCCx or SMCx if that channel is not enabled.

16.11.4 SMC General Parameter RAM Memory Map

Each SMCx parameter RAM area begins at the same offset from each base. The

protocol-specific portions of the SMCx parameter RAM are discussed in each mode. The

SMCx general parameter RAM shared by the UART and transparent protocols is described

in Table 16-36. The GCI protocol has its own parameter RAM.

You must initialize certain parameter RAM values before a serial management controller is

enabled. Other values are initialized or written by the communication processor module.

Once initialized, most parameter RAM values do not need to be accessed in your software

since most of the activity is centered around the transmit and receive buffer descriptors and

not the parameter RAM. However, if you access the parameter RAM, note the following

restrictions.

Figure 16-114. SMCx Memory Format

FRAME STATUS

DATA POINTER

FRAME STATUS

DATA LENGTH

DATA POINTER

POINTER TO SMCx

TX BD RING

RX DATA BUFFER

DUAL- PORT RAM

EXTERNAL MEMORY

TX BD RING

RX BD RING

TX DATA BUFFER

POINTER TO SMCx

RX BD RING

SMCx TX BD RING

SMCx RX BD RING

DATA LENGTH

MPC823 датащи(PDF) 4 Page - Motorola, Inc

MPC823 датащи(HTML) 4 Page - Motorola, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74

датащи скачать

ссылки URL