FULLDUPLEXSERIAL
Table of Contents |
FullDuplexSerial Object Version 1.2.2Object file: FullDuplexSerial.spin Version: 1.2.2 Date: 2006 - 2012 Author: Chip Gracey, Jeff Martin, Daniel Harris Company: Parallax Semiconductor Email: dharris@parallaxsemiconductor.com Licensing: MIT License - see end of file for terms of use. Revision History: v1.2.2 - 7/13/2012 Added extra comments to bring up to autodoc standard (msrobots) v1.2.1 - 5/1/2011 Added extra comments and demonstration code to bring up to gold standard. v1.2 - 5/7/2009 Fixed bug in dec method causing largest negative value (-2,147,483,648) to be output as -0. v1.1 - 3/1/2006 First official release. IntroductionThis driver, once started, implements a serial port in one cog.
Global CONstantshere you find CONstants used for the mode-parameter of the Start-method of this object. These constants can be added to be combined. for example serial#OCTX+serial#NOECHO SOURCE CODE... DEFAULTMODE = %000000 ' default mode INVERTRX = %000001 ' mode bit 0 = invert rx INVERTTX = %000010 ' mode bit 1 = invert tx OCTX = %000100 ' mode bit 2 = open-drain/source tx NOECHO = %001000 ' mode bit 3 = ignore tx echo on rx NOMODE = %000000 ' depreciated (msrobots/kurenko) PUBlic Spin methodsStart and StopStart and Stop methods are used for starting and stopping this object. This uses/frees one cog and the rx/tx-pins used.StopStop serial driver if it has already been started - frees the cog Parameters: none return: none example usage: serial.stop expected outcome of example usage call: Stops an already started serial port. SOURCE CODE... PUB Stop if cog cogstop(cog~ - 1) 'if the driver is already running, stop the cog longfill(@rx_head, 0, 9) 'zero out configuration variables Start(rxPin, txPin, mode, baudrate)Start serial driver - starts a cog Parameters: rxPin = Propeller pin to set up as RX-ing pin. Range = 0 - 31 txPin = Propeller pin to set up as TX-ing pin. Range = 0 - 31 mode = bitwise mode configuration variable, see mode bit description below. baudrate = baud rate to transmit bits at. you find CONstants for the mode-parameter in the CON section. These constants can be added to be combined. for example serial#OCTX+serial#NOECHO. return: Numeric value of the cog(1-8) that was started, false(0) if no cog is available. example usage: serial.start(31, 30, serial#NOMODE, 9_600) expected outcome of example usage call: Starts a serial port on Propller pins 30 and 31. The serial port does not invert the RX and TX data, no open-drain/source on the TX pin, does not ignore data echoed on RX pin, at 9,600 baud. SOURCE CODE... PUB Start(rxPin, txPin, mode, baudrate) : okay Stop 'make sure the driver isnt already running longfill(@rx_head, 0, 4) 'zero out the buffer pointers longmove(@rx_pin, @rxpin, 3) 'copy the start parameters to this objects pin variables bit_ticks := clkfreq / baudrate 'number of clock ticks per bit for the desired baudrate buffer_ptr := @rx_buffer 'save the address of the receive buffer okay := cog := cognew(@entry, @rx_head) + 1 'start the new cog now, assembly cog at "entry" label. Basic send/receiveHere you find basic send/receive-methods for single bytes.RxFlushContinuously pops the head of the receive buffer until no bytes remain. Parameters: none return: none example usage: serial.RxFlush expected outcome of example usage call: Receive bffer will be cleared. SOURCE CODE... PUB RxFlush repeat while RxCheck => 0 'Call RxCheck until buffer is empty RxCheckCheck if a byte is waiting in the receive buffer and return the byte if one is there, does NOT block (never waits). Parameters: none return: If no byte, then return(-1). If byte, then return(byte). example usage: serial.RxCheck expected outcome of example usage call: Return a byte if one is available, but dont wait for a byte to come in. SOURCE CODE... PUB RxCheck : rxByte rxByte-- 'make rxbyte = -1 if rx_tail <> rx_head 'if a byte is in the buffer, then rxByte := rx_buffer[rx_tail] ' grab it and store in rxByte rx_tail := (rx_tail + 1) & $F ' advance the buffer pointer RxTime(ms)Wait ms milliseconds for a byte to be received Parameters: ms = number of milliseconds to wait for a byte to be received. return: If no byte, then return(-1). If byte, then return(byte). example usage: serial.RxTime(500) expected outcome of example usage call: Wait half a second (500 ms) for a byte to be received. SOURCE CODE... PUB RxTime(ms) : rxByte | t t := cnt 'take note of the current time repeat until (rxByte := RxCheck) => 0 or (cnt - t) / (clkfreq / 1000) > ms RxReceive byte (may wait for byte) returns $00..$FF Parameters: none return: received byte example usage: serial.Rx expected outcome of example usage call: Wait until a byte has been received, then return that byte. SOURCE CODE... PUB Rx : rxByte repeat while (rxByte := RxCheck) < 0 'return the byte, wait while the buffer is empty Tx(txByte)Places a byte into the transmit buffer for transmission (may wait for room in buffer). Parameters: txByte = the byte to be transmitted return: none example usage: serial.Tx($0D) expected outcome of example usage call: Transmits the byte $0D serially on the txPin SOURCE CODE... PUB Tx(txByte) repeat until (tx_tail <> (tx_head + 1) & $F) 'wait until the buffer has room tx_buffer[tx_head] := txByte 'place the byte into the buffer tx_head := (tx_head + 1) & $F 'advance the buffer's pointer if rxtx_mode & %1000 'if ignoring rx echo Rx ' receive the echoed byte and discard Extended send/receiveHere you find extended send/receive-methods. This serial object has just extended send-methods.You can use them for formatted output of numbers and strings. Str(stringPtr)Transmit a string of bytes Parameters: stringPtr = the pointer address of the null-terminated string to be sent return: none example usage: serial.Str(@test_string) expected outcome of example usage call: Transmits each byte of a string at the address some_string. SOURCE CODE... PUB Str(stringPtr) repeat strsize(stringPtr) Tx(byte[stringPtr++]) 'Transmit each byte in the string Dec(value)Transmit the ASCII string equivalent of a decimal value Parameters: dec = the numeric value to be transmitted return: none example usage: serial.Dec(-1_234_567_890) expected outcome of example usage call: Will print the string "-1234567890" to a listening terminal. SOURCE CODE... PUB Dec(value) | i, x x := value == NEGX 'Check for max negative if value < 0 value := ||(value+x) 'If negative, make positive; adjust for max negative Tx("-") 'and output sign i := 1_000_000_000 'Initialize divisor repeat 10 'Loop for 10 digits if value => i Tx(value / i + "0" + x*(i == 1)) 'If non-zero digit, output digit; adjust for max negative value //= i 'and digit from value result~~ 'flag non-zero found elseif result or i == 1 Tx("0") 'If zero digit (or only digit) output it i /= 10 'Update divisor Hex(value, digits)Transmit the ASCII string equivalent of a hexadecimal number Parameters: value = the numeric hex value to be transmitted digits = the number of hex digits to print return: none example usage: serial.Hex($AA_FF_43_21, 8) expected outcome of example usage call: Will print the string "AAFF4321" to a listening terminal. SOURCE CODE... PUB Hex(value, digits) value <<= (8 - digits) << 2 repeat digits 'do it for the number of hex digits being transmitted Tx(lookupz((value <-= 4) & $F : "0".."9", "A".."F"))' Transmit the ASCII value of the hex characters Bin(value, digits)Transmit the ASCII string equivalent of a binary number Parameters: value = the numeric binary value to be transmitted digits = the number of binary digits to print return: none example usage: serial.Bin(%1110_0011_0000_1100_1111_1010_0101_1111, 32) expected outcome of example usage call: Will print the string "11100011000011001111101001011111" to a listening terminal. SOURCE CODE... PUB Bin(value, digits) value <<= 32 - digits repeat digits Tx((value <-= 1) & 1 + "0") 'Transmit the ASCII value of each binary digit Assembly CogSOURCE CODE... '*********************************** '* Assembly language serial driver * '*********************************** org ' ' ' Entry ' entry mov t1,par 'get structure address add t1,#4 << 2 'skip past heads and tails rdlong t2,t1 'get rx_pin mov rxmask,#1 shl rxmask,t2 add t1,#4 'get tx_pin rdlong t2,t1 mov txmask,#1 shl txmask,t2 add t1,#4 'get rxtx_mode rdlong rxtxmode,t1 add t1,#4 'get bit_ticks rdlong bitticks,t1 add t1,#4 'get buffer_ptr rdlong rxbuff,t1 mov txbuff,rxbuff add txbuff,#16 test rxtxmode,#%100 wz 'init tx pin according to mode test rxtxmode,#%010 wc if_z_ne_c or outa,txmask if_z or dira,txmask mov txcode,#transmit 'initialize ping-pong multitasking ' ' ' Receive ' receive jmpret rxcode,txcode 'run a chunk of transmit code, then return test rxtxmode,#%001 wz 'wait for start bit on rx pin test rxmask,ina wc if_z_eq_c jmp #receive mov rxbits,#9 'ready to receive byte mov rxcnt,bitticks shr rxcnt,#1 add rxcnt,cnt :bit add rxcnt,bitticks 'ready next bit period :wait jmpret rxcode,txcode 'run a chuck of transmit code, then return mov t1,rxcnt 'check if bit receive period done sub t1,cnt cmps t1,#0 wc if_nc jmp #:wait test rxmask,ina wc 'receive bit on rx pin rcr rxdata,#1 djnz rxbits,#:bit shr rxdata,#32-9 'justify and trim received byte and rxdata,#$FF test rxtxmode,#%001 wz 'if rx inverted, invert byte if_nz xor rxdata,#$FF rdlong t2,par 'save received byte and inc head add t2,rxbuff wrbyte rxdata,t2 sub t2,rxbuff add t2,#1 and t2,#$0F wrlong t2,par jmp #receive 'byte done, receive next byte ' ' ' Transmit ' transmit jmpret txcode,rxcode 'run a chunk of receive code, then return mov t1,par 'check for head <> tail add t1,#2 << 2 rdlong t2,t1 add t1,#1 << 2 rdlong t3,t1 cmp t2,t3 wz if_z jmp #transmit add t3,txbuff 'get byte and inc tail rdbyte txdata,t3 sub t3,txbuff add t3,#1 and t3,#$0F wrlong t3,t1 or txdata,#$100 'ready byte to transmit shl txdata,#2 or txdata,#1 mov txbits,#11 mov txcnt,cnt :bit test rxtxmode,#%100 wz 'output bit on tx pin according to mode test rxtxmode,#%010 wc if_z_and_c xor txdata,#1 shr txdata,#1 wc if_z muxc outa,txmask if_nz muxnc dira,txmask add txcnt,bitticks 'ready next cnt :wait jmpret txcode,rxcode 'run a chunk of receive code, then return mov t1,txcnt 'check if bit transmit period done sub t1,cnt cmps t1,#0 wc if_nc jmp #:wait djnz txbits,#:bit 'another bit to transmit? jmp #transmit 'byte done, transmit next byte ' ' ' Uninitialized data ' t1 res 1 t2 res 1 t3 res 1 rxtxmode res 1 bitticks res 1 rxmask res 1 rxbuff res 1 rxdata res 1 rxbits res 1 rxcnt res 1 rxcode res 1 txmask res 1 txbuff res 1 txdata res 1 txbits res 1 txcnt res 1 txcode res 1 Global VARiablesThis Object uses 18 longs of VAR space for each loaded instance. 8 Longs are used for rx/tx buffers. Since you can use multiple instances of this object in your main object, each has its own VAR section thus own buffers/pointers/Pins and a own cogid. But the loaded (DAT) Pasm-Code is shared reducing the overall footprint. if you need more then one serial object in your project. Each of the instances of this object needs a own cog. To run more ports with less cogs see fullDuplexSerial4port object. SOURCE CODE... long cog 'cog flag/id '9 longs, MUST be contiguous long rx_head long rx_tail long tx_head long tx_tail long rx_pin long tx_pin long rxtx_mode long bit_ticks long buffer_ptr byte rx_buffer[16] 'transmit and receive buffers byte tx_buffer[16] '16 bytes each License┌──────────────────────────────────────────────────────────────────────────────────────┐ │ TERMS OF USE: MIT License │ ├──────────────────────────────────────────────────────────────────────────────────────┤ │Permission is hereby granted, free of charge, to any person obtaining a copy of this │ │software and associated documentation files (the "Software"), to deal in the Software │ │without restriction, including without limitation the rights to use, copy, modify, │ │merge, publish, distribute, sublicense, and/or sell copies of the Software, and to │ │permit persons to whom the Software is furnished to do so, subject to the following │ │conditions: │ │ │ │The above copyright notice and this permission notice shall be included in all copies │ │or substantial portions of the Software. │ │ │ │THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, │ │INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A │ │PARTICULAR PURPOSE AND NONINFRINGEMENT. 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