288 lines
15 KiB
NASM
288 lines
15 KiB
NASM
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;===============================================================
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; Beamer control
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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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; GPIO definitions
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;---------------------------------------------------------------
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CONSTANT gpioBaseAddress, 0000
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CONSTANT gpioDataOffset, 0000
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CONSTANT gpioEnableOffset, 0001
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;---------------------------------------------------------------
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; UART definitions
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;---------------------------------------------------------------
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CONSTANT uartBaseAddress, 0010
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CONSTANT uartBaudOffset, 0002
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CONSTANT uartStatusOffset, 0001
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CONSTANT uartDataReady, 0001
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CONSTANT uartSending, 0002
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; CONSTANT uartBaudCount, 023D ; 66E6 / 115 200 = 573
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CONSTANT uartBaudCount, 0042 ; 66E6 / 1E6 = 66
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; CONSTANT uartpollDelay, 0100
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CONSTANT uartpollDelay, 0040
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CONSTANT commandNack, 0000
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CONSTANT commandWriteMem, 0003
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CONSTANT commandReadMem, 0004
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;---------------------------------------------------------------
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; beamer peripheral definitions
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;---------------------------------------------------------------
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CONSTANT beamerBaseAddress,0020
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CONSTANT beamerCtlOffset, 0000
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CONSTANT beamerSpeedOffset,0001
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CONSTANT beamerCtlInit, 0401
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; CONSTANT beamerCtlInit, 1001
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CONSTANT beamerSpeedInit, 0004
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;===============================================================
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; initializations
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;===============================================================
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;---------------------------------------------------------------
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; initialize GPIO
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;---------------------------------------------------------------
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LOAD s0, gpioBaseAddress
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ADD s0, gpioDataOffset
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LOAD s1, AA
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OUTPUT s1, (s0)
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LOAD s0, gpioBaseAddress
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ADD s0, gpioEnableOffset
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LOAD s1, 0F
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OUTPUT s1, (s0)
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;---------------------------------------------------------------
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; initialize UART
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;---------------------------------------------------------------
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LOAD s0, uartBaseAddress
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ADD s0, uartBaudOffset
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LOAD s1, uartBaudCount
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OUTPUT s1, (s0)
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;---------------------------------------------------------------
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; initialize beamer peripheral
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;---------------------------------------------------------------
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LOAD s0, beamerBaseAddress
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ADD s0, beamerCtlOffset
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LOAD s1, beamerCtlInit
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OUTPUT s1, (s0)
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LOAD s0, beamerBaseAddress
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ADD s0, beamerSpeedOffset
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LOAD s1, beamerSpeedInit
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OUTPUT s1, (s0)
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;===============================================================
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; Main loop
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;===============================================================
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;---------------------------------------------------------------
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; Process commands from serial port
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;---------------------------------------------------------------
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main: CALL uartGetCmd ; get command from UART
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COMPARE s3, 0000 ; check function return
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JUMP nz, commandAbort
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COMPARE s5, commandWriteMem ; check for WRITE_MEM command
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JUMP nz, commandRead
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OUTPUT s7, (s6) ; write word to memory location
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CALL sendWriteOk ; send write acknowledge
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JUMP main
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commandRead: INPUT s7, (s6) ; write word in memory location
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CALL sendReadData ; send back read data
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JUMP main
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commandAbort: CALL sendNAck
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JUMP main
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;===============================================================
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; Subroutines
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;===============================================================
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;---------------------------------------------------------------
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; Get command from serial port
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;---------------------------------------------------------------
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uartGetCmd: CALL uartGetByte ; get command header
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COMPARE s2, 00AA
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JUMP nz, uartGetCmd ; loop until byte is AAh
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LOAD s3, s2 ; prepare checksum
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CALL uartGetByte ; get packet id
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ADD s3, s2 ; calculate checksum
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LOAD s4, s2 ; store id for reply
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CALL uartGetByte ; get command
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ADD s3, s2 ; calculate checksum
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COMPARE s2, commandWriteMem ; check for WRITE_MEM command
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JUMP z , commandOk
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COMPARE s2, commandReadMem ; check for READ_MEM command
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JUMP z , commandOk
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JUMP commandKo ; no match
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commandOk: LOAD s5, s2 ; store command for action
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CALL uartGetByte ; get data length
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ADD s3, s2 ; calculate checksum
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COMPARE s5, commandWriteMem ; check for WRITE_MEM command
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JUMP z , testWrLength ; go to test write command length
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COMPARE s2, 0002 ; verify READ_MEM length
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JUMP nz, commandKo
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JUMP getAddress
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testWrLength: COMPARE s2, 0004 ; verify WRITE_MEM length
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JUMP nz, commandKo
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getAddress: CALL uartGetByte ; get address low
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ADD s3, s2 ; calculate checksum
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LOAD s6, s2 ; store address low
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CALL uartGetByte ; get address high
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ADD s3, s2 ; calculate checksum
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CALL shiftS2L8
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ADD s6, s2 ; build address from low and high
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COMPARE s5, commandReadMem ; check for READ_MEM command
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JUMP z , getChecksum ; skip reading data word
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CALL uartGetByte ; get data low
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ADD s3, s2 ; calculate checksum
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LOAD s7, s2 ; store data low
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CALL uartGetByte ; get data high
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ADD s3, s2 ; calculate checksum
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CALL shiftS2L8
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ADD s7, s2 ; build data from low and high
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getChecksum: CALL uartGetByte ; get checksum
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AND s3, 00FF ; limit calculated checksum to 8 bit
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COMPARE s3, s2 ; test checksum
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JUMP nz, commandKo
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LOAD s3, 0000 ; return OK
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RETURN
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commandKo: LOAD s3, 0001 ; return KO
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RETURN
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;---------------------------------------------------------------
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; send NACK reply
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;---------------------------------------------------------------
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sendNAck: LOAD s2, 00AA ; send header
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LOAD s3, s2 ; prepare checksum
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CALL uartSendByte
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LOAD s2, s4 ; packet id
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ADD s3, s2 ; calculate checksum
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CALL uartSendByte
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LOAD s2, commandNack ; negative Acknowledge
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ADD s3, s2 ; calculate checksum
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CALL uartSendByte
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LOAD s2, 0000 ; packet length: no data
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ADD s3, s2 ; calculate checksum
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CALL uartSendByte
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LOAD s2, s3 ; checksum
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CALL uartSendByte
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RETURN
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;---------------------------------------------------------------
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; send WRITE_MEM reply
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;---------------------------------------------------------------
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sendWriteOk: LOAD s2, 00AA ; send header
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LOAD s3, s2 ; prepare checksum
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CALL uartSendByte
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LOAD s2, s4 ; packet id
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ADD s3, s2 ; calculate checksum
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CALL uartSendByte
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LOAD s2, s5 ; received command
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ADD s3, s2 ; calculate checksum
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CALL uartSendByte
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LOAD s2, 0000 ; packet length: no data
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ADD s3, s2 ; calculate checksum
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CALL uartSendByte
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LOAD s2, s3 ; checksum
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CALL uartSendByte
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RETURN
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;---------------------------------------------------------------
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; send READ_MEM reply
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;---------------------------------------------------------------
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sendReadData: LOAD s2, 00AA ; send header
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LOAD s3, s2 ; prepare checksum
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CALL uartSendByte
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LOAD s2, s4 ; packet id
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ADD s3, s2 ; calculate checksum
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CALL uartSendByte
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LOAD s2, s5 ; received command
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ADD s3, s2 ; calculate checksum
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CALL uartSendByte
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LOAD s2, 0002 ; packet length: 2 bytes
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ADD s3, s2 ; calculate checksum
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CALL uartSendByte
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LOAD s2, s7 ; data low
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AND s2, 00FF ; keep low byte only
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ADD s3, s2 ; calculate checksum
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CALL uartSendByte
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LOAD s2, s7 ; data high
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CALL shiftS2R8 ; shift MSBs down to LSBs
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ADD s3, s2 ; calculate checksum
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CALL uartSendByte
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LOAD s2, s3 ; checksum
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CALL uartSendByte
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RETURN
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;---------------------------------------------------------------
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; Get byte from serial port
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;---------------------------------------------------------------
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uartGetByte: LOAD s0, uartBaseAddress ; read UART satus register
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ADD s0, 01
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;load s8, 0100
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checkStat: LOAD s2, uartpollDelay ; add delay between bus reads
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delay0: SUB s2, 0001
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JUMP nz, delay0
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;sub s8, 0001
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;jump nz, continue
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;load s2, 0035
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;call uartSendByte
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;load s8, 0100
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continue: INPUT s1, (s0)
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INPUT s1, (s0)
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TEST s1, uartDataReady ; check "data ready" bit
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JUMP z , checkStat ; loop until bit is '1'
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LOAD s0, uartBaseAddress ; read UART data register
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INPUT s2, (s0)
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INPUT s2, (s0)
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;LOAD s8, s2
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RETURN
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;---------------------------------------------------------------
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; Send byte to serial port
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;---------------------------------------------------------------
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uartSendByte: LOAD s0, uartBaseAddress ; read UART satus register
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ADD s0, uartStatusOffset
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readStatus: INPUT s1, (s0)
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INPUT s1, (s0)
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TEST s1, uartSending ; check "sending data" bit
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JUMP z , sendByte ; loop until bit is '1'
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LOAD s1, uartpollDelay ; add delay between bus reads
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delay1: SUB s1, 0001
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JUMP nz, delay1
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JUMP readStatus
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sendByte: LOAD s0, uartBaseAddress ; write UART data register
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OUTPUT s2, (s0)
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RETURN
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;---------------------------------------------------------------
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; shift s2 8 bits to the left
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;---------------------------------------------------------------
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shiftS2L8: LOAD s0, 8 ; loop count
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shiftLeftLoop: SL0 s2
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SUB s0, 0001
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JUMP nz, shiftLeftLoop
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RETURN
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;---------------------------------------------------------------
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; shift s2 8 bits to the right
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;---------------------------------------------------------------
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shiftS2R8: LOAD s0, 8 ; loop count
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shiftRightLoop: SR0 s2
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SUB s0, 0001
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JUMP nz, shiftRightLoop
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RETURN
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;===============================================================
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; End of instruction memory
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;===============================================================
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ADDRESS 3FF
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endOfMemory: JUMP endOfMemory
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