Prop-SX - 8 Servos plus 8 PWM with VSA

For those that need more than digital control of channels P8 to P15 the program below converts them to PWM outputs. Now you you can control the brightness of the LED spots on your talking skull.

VSA project setup: Channels: 0 to 15

Channels 0 to 7:
  * MiniSSC Servo
  * +Value = 240
  * -Value = 60
  * Default = 150

Channels 8 to 15:
  * MiniSSC Dimmer or MiniSSC Relay
  * +Value = 254
  * -Value = 0
  * Default = 0

Note that channels 8 to 15 can be setup as a dimmer or relay; use a relay if you're only going to be doing on/off control with a given channel in that range.

[Edit]: Posted updated version 25 OCT 2009

' =========================================================================
'
' File...... VSA_Servo8_PWM8.SXB
' Purpose...
' Author.... Jon Williams, EFX-TEK
' Copyright (c) 2008-2009 EFX-TEK
' Some Rights Reserved
' -- see http://creativecommons.org/licenses/by/3.0/
' E-mail.... jwilliams@efx-tek.com
' Started...
' Updated... 25 OCT 2009
'
' =========================================================================

' -------------------------------------------------------------------------
' Program Description
' -------------------------------------------------------------------------
'
' Servo/PWM controller designed for use with VSA or other real-time
' serial control programs.
'
' P0 to P7... Servo control
' P8 to P15... PWM/Digital outputs
'
' The protocol is identical to the SEETRON (www.seetron.com) MiniSSC:
'
' <sync><channel><value>
'
' sync...... $FF (255)
'
' channel... 0 to 7 for servos
' 8 to 15 for PWM/digital outputs
'
' value..... 60 to 240 for servos (150 = center)
' 0 to 254 for pwm outputs
'
' In VSA define servo channels as MiniSSC servo using 240, 60, 150 as the
' settings, and pwm channels as MiniSSC dimmer using 254 (max) and 0 (min).
' For digital behavior of a PWM output (e.g., for a valve) use MiniSSC
' Relay with an on value of 254 and off value of 0.
'
' Note: Servo min/max range is based on 180 values for Hitec servos, and
' this program reverses the VSA values to match them.

' -------------------------------------------------------------------------
' Conditional Compilation Symbols
' -------------------------------------------------------------------------

' -------------------------------------------------------------------------
' Device Settings
' -------------------------------------------------------------------------

ID "VSA_S8P8"

DEVICE SX28, OSCHS2, BOR42
FREQ 50_000_000

' -------------------------------------------------------------------------
' I/O Pins
' -------------------------------------------------------------------------

PwmCtrl PIN RC OUTPUT ' PWM control pins
Pwm7 PIN RC.7 ' use P15/OUT15
Pwm6 PIN RC.6 ' use P14/OUT14
Pwm5 PIN RC.5 ' use P13/OUT13
Pwm4 PIN RC.4 ' use P12/OUT12
Pwm3 PIN RC.3 ' use P11/OUT11
Pwm2 PIN RC.2 ' use P10/OUT10
Pwm1 PIN RC.1 ' use P9/OUT9
Pwm0 PIN RC.0 ' use P8/OUT8

ServoCtrl PIN RB OUTPUT ' servo control pins
Servo7 PIN RB.7 ' use P7
Servo6 PIN RB.6 ' use P6
Servo5 PIN RB.5 ' use P5
Servo4 PIN RB.4 ' use P4
Servo3 PIN RB.3 ' use P3
Servo2 PIN RB.2 ' use P2
Servo1 PIN RB.1 ' use P1
Servo0 PIN RB.0 ' use P0

TX PIN RA.3 OUTPUT ' to PC
RX PIN RA.2 INPUT ' from PC
SCL PIN RA.1 INPUT ' EE clock line (I2C)
SDA PIN RA.0 INPUT ' EE data line (I2C)

' Note: TX, SCL, and SDA lines are not used by this program

' -------------------------------------------------------------------------
' Constants
' -------------------------------------------------------------------------

IsOn CON 1
IsOff CON 0

Yes CON 1
No CON 0

LO_LIMIT CON 60 ' to prevent servo burn-up
HI_LIMIT CON 240

SYNC CON 255

' Bit dividers for 3.255us interrupt
' -- actual code runs at 3.33us (within tolerance for bit sampling)

Baud9600 CON 32
Baud19K2 CON 16
Baud38K4 CON 8

Baud1x0 CON Baud38K4 ' 1 bit period (ISR counts)
Baud1x5 CON Baud1x0 * 3 / 2 ' 1.5 bit periods

' -------------------------------------------------------------------------
' Variables
' -------------------------------------------------------------------------

flags VAR Byte ' (keep global)
isrFlag VAR flags.0
rxReady VAR flags.1

pwmTemp VAR Byte ' (keep global)
global3 VAR Byte

cmd VAR Byte ' SSC packet
chan VAR Byte
value VAR Byte
tValue VAR Word

rxSerial VAR Byte (16)
rxBuf VAR rxSerial(0) ' 8-byte buffer
rxCount VAR rxSerial(8) ' rx bit count
rxDivide VAR rxSerial(9) ' bit divisor timer
rxByte VAR rxSerial(10) ' recevied byte
rxHead VAR rxSerial(11) ' buffer head (write to)
rxTail VAR rxSerial(12) ' buffer tail (read from)
rxBufCnt VAR rxSerial(13) ' # bytes in buffer

pwmData VAR Byte (16) ' bank for pwm vars
level VAR pwmData(0)
level0 VAR pwmData(0)
level1 VAR pwmData(1)
level2 VAR pwmData(2)
level3 VAR pwmData(3)
level4 VAR pwmData(4)
level5 VAR pwmData(5)
level6 VAR pwmData(6)
level7 VAR pwmData(7)
acc0 VAR pwmData(8)
acc1 VAR pwmData(9)
acc2 VAR pwmData(10)
acc3 VAR pwmData(11)
acc4 VAR pwmData(12)
acc5 VAR pwmData(13)
acc6 VAR pwmData(14)
acc7 VAR pwmData(15)

svoData VAR Byte (16) ' bank servo data
pos VAR svoData(0) ' position table
pos0 VAR svoData(0)
pos1 VAR svoData(1)
pos2 VAR svoData(2)
pos3 VAR svoData(3)
pos4 VAR svoData(4)
pos5 VAR svoData(5)
pos6 VAR svoData(6)
pos7 VAR svoData(7)
svoTix VAR svoData(8) ' isr divider
svoFrame_LSB VAR svoData(9) ' frame timer
svoFrame_MSB VAR svoData(10)
svoIdx VAR SvoData(11) ' active servo pointer
svoTimer VAR svoData(12) ' pulse timer
svoPin VAR svoData(13) ' active servo pin

' =========================================================================
  INTERRUPT NOPRESERVE 300_000 ' (4) run every 3.333 uS
' =========================================================================

Mark_ISR:
  \ SETB isrFlag ' (1)

' -------
' RX UART
' -------
'
' UART code by C. Gracey, A. Williams, et al
' -- buffer and flow control mods by Jon Williams
'
Receive:
  ASM
   BANK rxSerial ' (1)
   JB rxBufCnt.3, RX_Done ' (2/4) skip if buffer is full
   MOVB C, RX ' (4) sample serial input
   TEST rxCount ' (1) receiving now?
   JNZ RX_Bit ' (2/4) yes, get next bit
   MOV W, #9 ' (1) no, prep for next byte
   SC ' (1/2)
   MOV rxCount, W ' (1) if start, load bit count
   MOV rxDivide, #Baud1x5 ' (2) prep for 1.5 bit periods

RX_Bit:
   DJNZ rxDivide, RX_Done ' (2/4) complete bit cycle?
   MOV rxDivide, #Baud1x0 ' (2) yes, reload bit timer
   DEC rxCount ' (1) update bit count
   SZ ' (1/2)
   RR rxByte ' (1) position for next bit
   SZ ' (1/2)
   JMP RX_Done ' (3)

RX_Buffer:
   MOV W, #rxBuf ' (1) point to buffer head
   ADD W, rxHead ' (1)
   MOV FSR, W ' (1)
   MOV IND, rxByte ' (2) move rxByte to head
   INC rxHead ' (1) update head
   CLRB rxHead.3 ' (1) keep 0..7
   INC rxBufCnt ' (1) update buffer count
   SETB rxReady ' (1) set ready flag

RX_Done:
  ENDASM

' --------------
' PWM Processing
' --------------
'
Process_PWM:
  ASM
   BANK pwmData ' (1)
   ADD acc0, level0 ' (2)
   RR pwmTemp ' (1)
   ADD acc1, level1 ' (2)
   RR pwmTemp ' (1)
   ADD acc2, level2 ' (2)
   RR pwmTemp ' (1)
   ADD acc3, level3 ' (2)
   RR pwmTemp ' (1)
   ADD acc4, level4 ' (2)
   RR pwmTemp ' (1)
   ADD acc5, level5 ' (2)
   RR pwmTemp ' (1)
   ADD acc6, level6 ' (2)
   RR pwmTemp ' (1)
   ADD acc7, level7 ' (2)
   RR pwmTemp ' (1)
   MOV PwmCtrl, pwmTemp ' (2)
  ENDASM

' ----------------
' Servo Processing
' ----------------
'
Test_Servo_Tix:
  ASM
   BANK svoData ' (1)
   INC svoTix ' (1) update divider
   CJB svoTix, #3, Servo_Done ' (4/6) done?
   CLR svoTix ' (1) yes, reset for next

' Code below this point runs every 10 uS

Check_Frame_Timer:
   CJNE svoFrame_LSB, #2000 & 255, Inc_FrTmr ' (4/6) svoFrame = 2000 (20 ms)?
   CJNE svoFrame_MSB, #2000 >> 8, Inc_FrTmr ' (4/6)
   CLR svoFrame_LSB ' (1) yes, reset
   CLR svoFrame_MSB ' (1)
   MOV svoPin, #%00000001 ' (2) start servo sequence
   CLR svoIdx ' (1) point to servo 0
   MOV FSR, #pos ' (2)
   MOV svoTimer, IND ' (2)
   JMP Refesh_Servo_Outs ' (3)

Inc_FrTmr:
   INC svoFrame_LSB ' (1) INC svoFrame
   ADDB svoFrame_MSB, Z ' (2)

Check_Servo_Timer:
   TEST svoPin ' (1) any servos on?
   SNZ ' (1)
   JMP Servo_Done ' (1) no, exit
   DEC svoTimer ' (1) yes, update timer
   SZ ' (1) still running?
   JMP Servo_Done ' (1) yes, exit

Reload_Servo_Timer:
   INC svoIdx ' (1) point to next servo
   CLRB svoidx.3 ' (1) keep 0 - 7
   MOV W, #pos ' (1) get pulse timing
   ADD W, svoIdx ' (1)
   MOV FSR, W ' (1)
   MOV W, IND ' (1)
   MOV svoTimer, W ' (1) move to timer

Select_Next_Servo:
   CLC ' (1)
   RL svoPin ' (1)

Refesh_Servo_Outs:
   MOV ServoCtrl, svoPin ' (2) update outputs

Servo_Done:
  ENDASM

ISR_Exit:
  RETURNINT ' (4)

' -------------------------------------------------------------------------
' Subroutine / Function Declarations
' -------------------------------------------------------------------------

FLUSH_RX SUB 0 ' clear RX buffer
RX_BYTE FUNC 1, 0 Byte ' receive a byte

DELAY_MS SUB 2, 2, Word ' delay in 1ms units

' =========================================================================
  PROGRAM Start
' =========================================================================

Start:
  TX = 1 ' set TX line to idle
  DELAY_MS 50
  FLUSH_RX

  ' center servos
  PUT pos, 150 , 150, 150, 150, 150, 150, 150, 150

Main:
  cmd = RX_BYTE
  IF cmd <> SYNC THEN Main

Get_Channel:
  chan = RX_BYTE
  IF chan = SYNC THEN Get_Channel ' correct for re-sync
  IF chan > 15 THEN Main ' check channel range

Get_Value:
  value = RX_BYTE
  IF value = $FF THEN Get_Channel ' correct for re-sync

Process_Value:
  IF chan < 8 THEN ' servo channel?
   value = value MIN LO_LIMIT ' force to legal limits
   value = value MAX HI_LIMIT
   value = HI_LIMIT - value ' invert to match VSA
   value = value + LO_LIMIT
   pos(chan) = value
  ELSE
   chan = chan & $07 ' adjust for PWM port
   tValue = value * value ' linearize; x = (x*x)/256
   level(chan) = tValue_MSB ' update pwm channel
  ENDIF

  GOTO Main

' -------------------------------------------------------------------------
' Subroutine / Function Code
' -------------------------------------------------------------------------

' Use: FLUSH_RX
' -- flushes pending bytes in rx buffer
' -- waits on incoming byte if in process

SUB FLUSH_RX
  ASM
   BANK rxSerial ' point to serial vars
   TEST rxCount ' receiving now?
   JNZ @FLUSH_RX ' let it finish
   CLR rxHead ' clear buffer pointers
   CLR rxTail
   CLR rxBufCnt ' clear buffer count
   BANK $00
   CLRB rxReady ' clear ready flag
  ENDASM
  ENDSUB

' -------------------------------------------------------------------------

' Use: aByte = RX_BYTE
' -- returns "aByte" from 8-byte circular buffer
' -- will wait if buffer is presently empty
' -- rxBufCnt holds byte count of receive buffer (0 to 8)

FUNC RX_BYTE
  ASM
   JNB rxReady, @$ ' wait if empty
   BANK rxSerial ' point to serial vars
   MOV W, #rxBuf
   ADD W, rxTail ' point to rxBuf(rxTail
   MOV FSR, W
   MOV __PARAM1, IND ' get byte at tail
   INC rxTail ' update tail
   CLRB rxTail.3 ' keep 0..7
   DEC rxBufCnt ' update buffer count
   SNZ ' exit if not zero
   CLRB rxReady ' else clear ready flag
   BANK $00
  ENDASM
  ENDFUNC

' -------------------------------------------------------------------------

' Use: DELAY_MS duration
' -- delay in milliseconds

SUB DELAY_MS
  ms VAR __WPARAM12
  msTix VAR __WPARAM34

  DO WHILE ms > 0
   msTix = 300 ' load 1 ms timer
   DO WHILE msTix > 0 ' let timer expire
   \ CLRB isrFlag ' clear ISR flag
   \ JNB isrFlag, @$ ' wait for flag to be set
   DEC msTix ' update 1 ms timer
   LOOP
   DEC ms ' update delay timer
  LOOP
  ENDSUB

' =========================================================================
' User Data
' =========================================================================