METHOD FOR SENSING AND MANAGING MESSAGE BUFFER FULL USING DUAL PORT RAM

摘要

PURPOSE: A method for sensing and managing message buffer pull using a dual port ram is provided to instantly sense buffer full by transmitting and receiving control information between a master board and a slaver board via a DPRAM and reduce load of a processor by reporting buffer full or termination mutually. CONSTITUTION: Functions of a master board and a slaver board are initialized(S310). The master board is operated as master basic functions of sensing obstacles and managing the slaver board, transmitting a message to the slaver board, and receiving the message from the slaver board(S320-S323). The master board confirms the method for sensing buffer full in methods 1 and 2 before transmitting the message(S330). If method 1 is set up, the master board reads current transmission buffer write pointer(TXWP) in a control information area for confirming whether buffer flag of the corresponding write pointer is empty(S340). If empty, the master board stores the message in a transmission buffer indicated by the TXWP and changes the flag from empty to use(S390). The master board increases the value of the TXWP and changes the TXWP value with a transmission starting address(TXSA)(S391). If not empty, the master board generates transmission buffer full interrupt to the slaver board(S370) and waits in idle state(S371). If the master board receives buffer full termination interrupt(S380), the master board reopens message transmission. If method 2 is set up, the master board reads transmission buffer and read and write pointers and calculates the number of the empty buffers for calculating buffer full degree(S350). The master board compares the set reference value with the buffer full degree for judging buffer full(S360).