316 lines
13 KiB
ObjectPascal
316 lines
13 KiB
ObjectPascal
{
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beamer.pas
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The beamer controller polls the UART to get commands and provides the
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corresponding replies.
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}
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program BeamerControl;
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{==============================================================================}
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{ Constants }
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{==============================================================================}
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const
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clockFrequency = 66E6;
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gpioBaseAddress = $0000;
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gpioDataOffset = $0000;
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gpioEnableOffset = $0001;
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uartBaseAddress = $0010;
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uartBaudOffset = $0002;
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uartStatusOffset = $0001;
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uartDataReady = $0001;
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uartSending = $0002;
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uartBaudRate = 1E6;
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uartBaudCount = clockFrequency / uartBaudRate;
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uartpollDelay = uartBaudCount / 2;
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commandHeader = $AA;
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commandNack = $00;
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commandWriteMem = $03;
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commandReadMem = $04;
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commandWriteLength = 4;
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commandReadLength = 2;
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beamerBaseAddress = $0020;
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beamerCtlOffset = $0000;
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beamerSpeedOffset = $0001;
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beamerCtlInit = $0401;
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beamerSpeedInit = $0004;
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{==============================================================================}
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{ Variables }
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{==============================================================================}
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var
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packetId, commandId, errorId: uint8;
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memoryAddress, memoryData: word;
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{==============================================================================}
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{ Procedures and functions }
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{==============================================================================}
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{============================================================================}
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{ Register-level accesses }
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{============================================================================}
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{----------------------------------------------------------------------------}
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{ Registers initializations }
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{----------------------------------------------------------------------------}
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procedure initRegisters;
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begin
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{ initialize GPIO }
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mem[gpioBaseAddress+gpioDataOffset] := $AA;
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mem[gpioBaseAddress+gpioEnableOffset] := $0F;
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{ initialize UART }
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mem[uartBaseAddress+uartBaudOffset] := uartBaudCount;
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{ initialize beamer peripheral }
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mem[beamerBaseAddress+beamerCtlOffset] := beamerCtlInit;
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mem[beamerBaseAddress+beamerSpeedOffset] := beamerSpeedInit;
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end;
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{----------------------------------------------------------------------------}
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{ Get byte from serial port }
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{----------------------------------------------------------------------------}
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procedure getSerialPortByte : uint8;
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var
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uartByte: uint8;
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begin
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{ poll until data byte available }
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uartByte := 0;
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while uartByte = 0 do
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begin
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{ spend time in order not to overcharge the AHB bus }
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for index := 1 to uartpollDelay do
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noOperation;
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{ read status register }
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uartByte := mem[uartBaseAddress+uartStatusOffset] and uartDataReady;
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end;
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{ read data register and return it }
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getSerialPortByte := mem[uartBaseAddress];
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end;
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{----------------------------------------------------------------------------}
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{ Send byte to serial port }
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{----------------------------------------------------------------------------}
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procedure sendSerialPort(uartByte : uint8);
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var
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statusByte: uint8;
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begin
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{ poll until ready to send }
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statusByte := mem[uartBaseAddress+uartStatusOffset] and uartSending;
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while statusByte = 0 do
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begin
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{ spend time in order not to overcharge the AHB bus }
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for index := 1 to uartpollDelay do
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noOperation;
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{ read status register }
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statusByte := mem[uartBaseAddress+uartStatusOffset] and uartSending;
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end;
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{ write data register }
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mem[uartBaseAddress] := uartByte;
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end;
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{============================================================================}
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{ Communication protocol }
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{============================================================================}
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{----------------------------------------------------------------------------}
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{ Get command }
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{----------------------------------------------------------------------------}
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function getCommand(
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var packetId, commandId, commandLength : uint8;
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var memoryAddress, memoryData : word
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) : uint8;
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var
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uartData: uint8;
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checksum: word;
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begin
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{ wait for new command header }
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uartData := 0;
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while uartData <> commandHeader do
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uartData := getSerialPortByte;
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checksum := uartData;
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{ get packet id }
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packetId := getSerialPortByte;
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checksum := checksum + packetId;
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{ get command }
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commandId := getSerialPortByte;
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checksum := checksum + commandId;
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{ process known commands }
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if (commandId = commandWriteMem) or (commandId = commandReadMem) then
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begin
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{ get command length }
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commandLength := getSerialPortByte;
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checksum := checksum + commandLength;
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{ check command lengths }
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if (commandId = commandWriteMem) and (commandLength <> commandWriteLength) then
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getCommand := 1;
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else if (commandId = commandReadMem) and (commandLength <> commandReadLength) then
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getCommand := 1;
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else
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begin
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{ get address }
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memoryAddress := getSerialPortByte;
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checksum := checksum + memoryAddress;
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memoryAddress := (memoryAddress shl 8) + getSerialPortByte;
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checksum := checksum + memoryAddress;
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{ get data }
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if commandId = commandReadMem then
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begin
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memoryData := getSerialPortByte;
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checksum := checksum + memoryData;
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memoryData := (memoryData shl 8) + getSerialPortByte;
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checksum := checksum + memoryData;
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end;
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{ get and verify checksum}
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if getSerialPortByte = (checksum and $00FF) then
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getCommand := 0;
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else
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getCommand := 1;
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end;
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end;
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else
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getCommand := 1;
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end;
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{----------------------------------------------------------------------------}
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{ Send NACK }
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{----------------------------------------------------------------------------}
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function sendNegativeAcknowledge(packetId : uint8);
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var
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uartData: uint8;
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checksum: word;
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begin
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{ send packet header }
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uartData := $AA;
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sendSerialPort(uartData);
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checksum := uartData;
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{ send packet id }
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uartData := packetId;
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sendSerialPort(uartData);
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checksum := checksum + uartData;
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{ send command id }
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uartData := commandNack;
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sendSerialPort(uartData);
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checksum := checksum + uartData;
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{ send packet length }
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uartData := 0;
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sendSerialPort(uartData);
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checksum := checksum + uartData;
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{ send checksum }
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uartData := checksum and $00FF;
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sendSerialPort(uartData);
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end;
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{----------------------------------------------------------------------------}
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{ Send ACK }
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{----------------------------------------------------------------------------}
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function sendAcknowledge(packetId, commandId : uint8);
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var
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uartData: uint8;
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checksum: word;
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begin
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{ send packet header }
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uartData := $AA;
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sendSerialPort(uartData);
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checksum := uartData;
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{ send packet id }
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uartData := packetId;
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sendSerialPort(uartData);
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checksum := checksum + uartData;
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{ send command id }
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uartData := commandId;
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sendSerialPort(uartData);
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checksum := checksum + uartData;
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{ send packet length }
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uartData := 0;
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sendSerialPort(uartData);
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checksum := checksum + uartData;
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{ send checksum }
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uartData := checksum and $00FF;
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sendSerialPort(uartData);
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end;
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{----------------------------------------------------------------------------}
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{ Send READ_MEM reply }
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{----------------------------------------------------------------------------}
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function sendReadAnswer(packetId : uint8; memoryData: word);
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var
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uartData: uint8;
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checksum: word;
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begin
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{ send packet header }
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uartData := $AA;
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sendSerialPort(uartData);
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checksum := uartData;
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{ send packet id }
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uartData := packetId;
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sendSerialPort(uartData);
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checksum := checksum + uartData;
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{ send command id }
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uartData := commandReadMem;
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sendSerialPort(uartData);
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checksum := checksum + uartData;
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{ send packet length }
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uartData := 2;
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sendSerialPort(uartData);
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checksum := checksum + uartData;
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{ send data low }
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uartData := memoryData and $00FF;
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sendSerialPort(uartData);
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checksum := checksum + uartData;
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{ send data high }
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uartData := memoryData shr 8;
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sendSerialPort(uartData);
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checksum := checksum + uartData;
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{ send checksum }
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uartData := checksum and $00FF;
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sendSerialPort(uartData);
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end;
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{==============================================================================}
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{ Main program }
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{==============================================================================}
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begin
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{ initialize SoC registers }
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initRegisters;
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{ main loop }
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while true do begin
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{ get a new command }
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errorId := getCommand(packetId, commandId, memoryAddress, memoryData);
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{ process command }
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if errorId = 0 then
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begin
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{ process write command }
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if commandId = commandWriteMem then
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begin
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mem[memoryAddress] := memoryData;
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sendAcknowledge(packetId, commandId);
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end;
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{ process read command }
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else if commandId = commandReadMem then
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begin
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memoryData := mem[memoryAddress];
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sendReadAnswer(packetId, memoryData);
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end;
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{ reply to unknown command }
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else
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sendNegativeAcknowledge(packetId);
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end;
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{ negative acknowledge on reception error }
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else
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sendNegativeAcknowledge(packetId);
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end;
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end.
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{
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;---------------------------------------------------------------
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; register definitions
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; s0, s1: used for INPUT and OUTPUT operations
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; S2: returns UART data byte
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; S3: uart protocol checksum
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; S4: uart protocol packet id
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; S5: uart protocol command id
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; S6: uart protocol address
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; S7: uart protocol data
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; S8: copy of UART data byte for debug
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;---------------------------------------------------------------
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}
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