在CSMA CDMA模式下,83C152微控制器的全球串行通

The 83C152 is an 80C51BH based microcontroller with DMA capabilities and a high speed, multi-protocol, synchronous serial communication interface called the
Global Serial Channel (GSC). The GSC uses packetized data frames that consist of a beginning of frame (BOF) flag, address byte(s), data byte(s), a Cyclic Redundancy
Check (CRC), and an End Of Frame (EOF) flag. An example of this type of packet is shown in Figure 1. Most 80C152 users will be familiar with UARTs, another type of serial interface. Figures 1 and 2 compare the two types of frames. The UART uses
start and stop bits with a data byte between as shown in Figure 2. The 83C152 retains the standard MCSÉ-51 UART.
CONTENTS PAGE
INTRODUCTION  1
GSC INITIALIZATION  9
INITIALIZATION (PROTOCOL
DEPENDENT)  9
Baud Rate  9
Preamble Length  10
Backoff Mode  10
Interframe Space  11
Jamming Signal  15
Slot Time  16
Addressing  16
INITIALIZATIONÐPROTOCOL
INDEPENDENT  18
Clearing Collision Counter  18
Control of the GSC  19
Initializing DMA  19
Initializing Counters and Pointers  20
Enabling Receiver and Receiver
Interrupts  20
Enabling Transmitter and Transmit
Interrupts  21
STARTING, MAINTAINING, AND
ENDING TRANSMISSIONS  22
STARTING, MAINTAINING, AND
ENDING RECEPTIONS  23
SUMMARY  24
SOFTWARE EXAMPLE  A-1
CONTROLLING THE BACKOFF
ALGORITHM  B-1
REFERENCES  C-1