Basic/source/SerialMirror.spin

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{{
SerialMirror.spin : V07.05.10
Derived from: Full-Duplex Serial Driver v1.1
┌────────────────────────────────────────────────┐
│ Copyright (c) 2007 Mirror / 2006 Parallax Inc. │
│ (See end of file for terms of use) │
└────────────────────────────────────────────────┘
It has been extended in the following ways:
1) Make allowance for different buffer sizes. I've set the default buffer to
64 bytes as this is large enough to contain a complete incoming/outgoing
message for my protocol.
2) Check for a stop bit!! If a stop bit is not present then the received byte
is dropped. No flags of any sort are set. It's up to a higher level of the
protocol to check the message for integrity.
3) Variables have been moved to DAT space.
The significance of this is not obvious at first, but what it means is that
every instance of this object shares the same variable space. Why do this?
If you have multiple nested objects, then serial comms can be added to all
of them. ONLY the top object must call the start method. The nested objects
then have full comms access. A simple example is:
┌────────────────────────────────────────────────────────────────────┐
│ APP_SerialMirror.spin │
├────────────────────────────────────────────────────────────────────┤
│CON │
│ _clkmode = xtal1 + pll16x │
│ _xinfreq = 5_000_000 │
│ │
│ BaudRate = 38400 'Baud │
│ RxPin = 31 'For RS232 │
│ TxPin = 30 'For RS232 │
│ CommsMode = %0000 'See SerialMirror.spin for meaning │
│ │
│OBJ │
│ Debug : "SerialMirror" │
│ Test : "TestObject" │
│ │
│PUB Start │
│ Debug.start(RxPin, TxPin, CommsMode, BaudRate) │
│ Test.SayHello │
└────────────────────────────────────────────────────────────────────┘
┌────────────────────────────────────────────────────────────────────┐
│ TestObject.spin │
├────────────────────────────────────────────────────────────────────┤
│OBJ │
│ Debug : "SerialMirror" │
│ │
│PUB SayHello │
│ Debug.str(string("Hello",13,10)) │
└────────────────────────────────────────────────────────────────────┘
4) This object is NOT suitable for driving multiple serial ports.
If you want multiple serial ports each with single object access, then
use FullDuplexSerial.
If you want serial comms through the same port from multiple objects,
then use THIS object.
If you want multiple serial ports each with multi-object usage, then copy
and rename this files for the number of unique serial ports.
5) Added GetNumber which will receive a number (positive or negative) from
the serial port in either decimal, binary or hexadecimal notation.
6) Added extra comments to the assembler section - for the newbies. I've been
doing this propeller stuff for a month now, so I guess that makes me an
old hand.
7) Added CrLf which does just that - purely a conveniance function for me.
}}
CON
'BEWARE BEWARE : buffer_length can be any one of:
' 2, 4, 8, 16, 32, 64, 128 or 256
' BUT, if you change it, you MUST also make sure that the rx_buffer and
' tx_buffer variables are adjusted in the DAT space. This is because there
' is no way to declare an array in DAT space, so the length must be
' manually defined.
buffer_length = 64
buffer_mask = buffer_length - 1
DAT
cog long 0 'cog flag/id
rx_head long 0 '9 contiguous longs
rx_tail long 0
tx_head long 0
tx_tail long 0
rx_pin long 0
tx_pin long 0
rxtx_mode long 0
bit_ticks long 0
buffer_ptr long 0
'Set these buffers to the buffer_length constant in bytes.
'longs are used as a shortcut - 1 long == 4 bytes.
rx_buffer long 0, 0, 0, 0, 0, 0, 0, 0 '32 bytes
long 0, 0, 0, 0, 0, 0, 0, 0 '64 bytes
tx_buffer long 0, 0, 0, 0, 0, 0, 0, 0 '32 bytes
long 0, 0, 0, 0, 0, 0, 0, 0 '64 bytes
PUB start(rxpin, txpin, mode, baudrate) : okay
{{
Start serial driver - starts a cog
returns false if no cog available
mode bit 0 = invert rx
mode bit 1 = invert tx
mode bit 2 = open-drain/source tx
mode bit 3 = ignore tx echo on rx
}}
stop
longfill(@rx_head, 0, 4)
longmove(@rx_pin, @rxpin, 3)
bit_ticks := clkfreq / baudrate
buffer_ptr := @rx_buffer
okay := cog := cognew(@entry, @rx_head) + 1
PUB stop
{{
Stop serial driver - frees a cog
}}
if cog
cogstop(cog~ - 1)
longfill(@rx_head, 0, 9)
PUB rxflush
{{
Flush receive buffer
}}
repeat while rxcheck => 0
PUB rxcheck : rxbyte
{{
Check if byte received (never waits)
returns -1 if no byte received, $00..$FF if byte
}}
rxbyte--
if rx_tail <> rx_head
rxbyte := byte[@rx_buffer][rx_tail]
rx_tail := (rx_tail + 1) & buffer_mask
PUB rxtime(ms) : rxbyte | t
{{
Wait ms milliseconds for a byte to be received
returns -1 if no byte received, $00..$FF if byte
}}
t := cnt
repeat until (rxbyte := rxcheck) => 0 or (cnt - t) / (clkfreq / 1000) > ms
PUB rx : rxbyte
{{
Receive byte (may wait for byte)
returns $00..$FF
}}
repeat while (rxbyte := rxcheck) < 0
PUB tx(txbyte)
{{
Send byte (may wait for room in buffer)
}}
'Wait till there's space in the Tx buffer
repeat until (tx_tail <> (tx_head + 1) & buffer_mask)
byte[@tx_buffer][tx_head] := txbyte
tx_head := (tx_head + 1) & buffer_mask
if rxtx_mode & %1000
rx
PUB str(stringptr)
{{
Send string
}}
repeat strsize(stringptr)
tx(byte[stringptr++])
PUB dec(value) | i
{{
Print a decimal number
}}
if value < 0
-value
tx("-")
i := 1_000_000_000
repeat 10
if value => i
tx(value / i + "0")
value //= i
result~~
elseif result or i == 1
tx("0")
i /= 10
PUB hex(value, digits)
{{
Print a hexadecimal number
}}
value <<= (8 - digits) << 2
repeat digits
tx(lookupz((value <-= 4) & $F : "0".."9", "A".."F"))
PUB bin(value, digits)
{{
Print a binary number
}}
value <<= 32 - digits
repeat digits
tx((value <-= 1) & 1 + "0")
PUB GetNumber : value | base, digit, cmd, negative
{{
Get a number from the serial port. The number may start with a "-" if its
negative. This may be followed by digits for a decimal number, "%" then
0..1's for a binary number and "$" then digits or "A".."F" (or "a".."f")
for a hexidecimal number. The first illegal character terminates number
entry.
}}
negative := 1
value := 0
base := 10
cmd := rx
if cmd == "-"
negative := -1
cmd := rx
if cmd == "%"
base := 2
elseif cmd == "$"
base := 16
else
value := lookdown(cmd : "0".."9") - 1
if value < 0
abort
repeat
cmd := rx
if base == 10
digit := lookdown(cmd : "0".."9") - 1
elseif base == 2
digit := lookdown(cmd : "0".."1") - 1
elseif base == 16
digit := lookdown(cmd : "0".."9", "A".."F", "a".."f") - 1
if digit => 16 'Compensate for the lower case letters
digit -= 6
if digit < 0 'All done?
return value * negative
value := value * base + digit
PUB CrLf
{{
Send a carriage return linefeed combination.
}}
tx(13)
tx(10)
DAT
'***********************************
'* Assembly language serial driver *
'***********************************
org 0
'
'
' 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 '... for the receiver
mov txbuff,rxbuff '... and the transmitter
add txbuff,#buffer_length
test rxtxmode,#%100 wz 'if_nz = open drain Tx
test rxtxmode,#%010 wc 'if_c = inverted output
if_z_ne_c or outa,txmask
if_z or dira,txmask
mov rxcode,#0 'for Gear debugger
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 'half a bit tick
add rxcnt,cnt '+ the current clock
:bit add rxcnt,bitticks 'ready for the middle of the 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 into carry
rcr rxdata,#1 'shift carry into receiver
djnz rxbits,#:bit 'go get another bit till done
test rxtxmode,#%001 wz 'find out if rx is inverted
if_z_ne_c jmp #receive 'abort if no stop bit
shr rxdata,#32-9 'justify and trim received byte
and rxdata,#$FF
if_nz xor rxdata,#$FF 'if rx inverted, invert byte
rdlong t2,par 'rx_head
add t2,rxbuff 'plus the buffer offset
wrbyte rxdata,t2 'write the byte
sub t2,rxbuff
add t2,#1 'update rx_head
and t2,#buffer_mask
wrlong t2,par 'and save
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 'tx_head
rdlong t2,t1
add t1,#1 << 2 'tx_tail
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,#buffer_mask
wrlong t3,t1
or txdata,#$100 'or in a stop bit
shl txdata,#2
or txdata,#1 'or in a idle line state and a start bit
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
{{
┌───────────────────────────────────────────────────────────────────────────┐
│ 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. IN NO EVENT SHALL THE│
│ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER │
│ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING │
│ FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER │
│ DEALINGS IN THE SOFTWARE. │
└───────────────────────────────────────────────────────────────────────────┘
}}