;****************************************************************************** ;* Software License Agreement * ;* The software supplied herewith by Microchip Technology Incorporated * ;* (the "Company") is intended and supplied to you, the Company's * ;* customer, for use solely and exclusively on Microchip products. * ;* * ;* The software is owned by the Company and/or its supplier, and is * ;* protected under applicable copyright laws. All rights are reserved. * ;* Any use in violation of the foregoing restrictions may subject the * ;* user to criminal sanctions under applicable laws, as well as to * ;* civil liability for the breach of the terms and conditions of this * ;* license. * ;* * ;* THIS SOFTWARE IS PROVIDED IN AN "AS IS" CONDITION. NO WARRANTIES, * ;* WHETHER EXPRESS, IMPLIED OR STATU-TORY, INCLUDING, BUT NOT LIMITED * ;* TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A * ;* PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. THE COMPANY SHALL NOT, * ;* IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL OR * ;* CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER. * ;* * ;****************************************************************************** ;***** Key State machine module * ;* This module handles the key debounce and decoding for the system. It * ;* decodes three seperate key conditions; PRESS: a key press of less than 1.5 * ;* seconds, PUSH: a key press of 1.5 to 3.0 seconds, and HOLD: the hold of the* ;* key for more than 3.0 seconds. In addition, the HOLD command features an * ;* auto repeat at a 3.0 second interval. A KEYPRESS output is also available * ;* to allow the command decoder to determine that the key HOLD is complete. * ;* * ;* State Machine Variable List. * ;* NAME DIRECTION RANGE SOURCE/DESTINATION * ;* tstats.dokey input 0-1 key state machine * ;* bcounter local 0-7 debounce counter * ;* stats.keypress output 0-1 current status of key * ;* stats.press output 0-1 press decoded * ;* stats.push output 0-1 push decoded * ;* stats.hold output 0-1 hold decoded * ;* stats.k_error output 0-1 error condition * ;* khold_timer local 0-150 delay timer for repeat* ;* * ;* Key Task: State machine design * ;* Execution indexed state machine * ;* * ;* State * ;* 0 Idle no key pressed * ;* 1 press key held < 1.5 sec * ;* 2 push key held < 3.0 sec * ;* 3 hold key held > 3.0 sec * ;* 4 delay auto repeat delay for hold * ;* 5 default error state * ;* 6 default error state * ;* 7 default error state * ;* * ;* STATE TO STATE TRANSITIONS * ;* From Conditional True False comments * ;* -------------------------------------------------------------------------- * ;* Idle if keypress detected press Idle no key * ;* * ;* press if keypress = 0 Idle press key stable at open press * ;* press is time > 1.5 sec push press if held > 1.5 s then push * ;* * ;* push if keypress = 0 Idle push key stable at open Push * ;* push if time > 3.0 sec hold push if held > 3.0 s then hold * ;* * ;* hold if keypress = 0 Idle hold key stable at open hold * ;* hold delay ---- goto delay for auto repeat * ;* * ;* delay if keypress = 0 Idle delay key stable at open delay * ;* delay if time = 3.0 sec hold delay auto repeat * ;* * ;* ACTIONS * ;* Idle none * ;* press if release send press command * ;* push if release send push command * ;* hold send hold command * ;* delay delay 3.0 seconds then return to hold * ;* * ;* Code segment prior to state variable decoder, monitors the button and * ;* debounces with keypress as an output. * ;* (Algorithm) * ;* * ;* if (key == 0) and (bcounter < 7) then bcounter++ * ;* if (key == 1) and (bcounter > 0) then bcounter-- * ;* if bcounter == 6 then keypress = 1 * ;* if bcounter == 2 then keypress = 0 * ;* * ;* * ;* INPUT/OUTPUT * ;* input output * ;* Idle keypress ---- * ;* press keypress press cmd * ;* push keypress push cmd * ;* hold keypress hold cmd * ;* delay keypress ---- * ;* * ;****************************************************************************** Key btfss tstats,dokey ; test timer flag for execution of state machine return bcf tstats,dokey btfsc GPIO,3 ;btn ; test the state of the button goto buttonup ; if open debounce end of key buttondown ; if down debounce key press incf bcounter,f ; if down then increment the counter btfsc bcounter,3 ; check for an overflow decf bcounter,f ; if over back up 1 count movlw 0x06 ; load for hiside hysteresis test of counter xorwf bcounter,w btfsc STATUS,Z ; if bcounter = 6 then set key press flag bsf kstats,keypress goto key_machine buttonup decf bcounter,f ; if up then decrement counter btfsc bcounter,7 ; test for underflow incf bcounter,f ; if under back up 1 count movlw 0x02 ; load for loside hysteresis test of counter xorwf bcounter,w btfsc STATUS,Z ; if bcounter =2 then clear key press flag bcf kstats,keypress key_machine ; start of key press state machine movf key_state,w ; verify state variable is in range 0-7 andlw 0xF8 btfss STATUS,Z goto K_default ; if upper bits set, then error movlw key_sm_tab / 0x100 ; if in range then use jump table to decode state movwf PCLATH ; set the Program counter Latch High to MSB movf key_state,w andlw 0x07 ; add table address to state value to get pointer addlw key_sm_tab & 0xFF movwf PCL ; computed goto key_sm_tab goto K_Idle ; waiting goto K_press ; short press < 1.5 seconds goto K_push ; longer press < 3.0 seconds goto K_hold ; longest press > 3.0 seconds goto K_delay ; delay for hold autorepeat goto K_default ; error goto K_default ; error goto K_default ; error ;***** KEY TASK STATE MACHINE, IDLE STATE K_Idle clrf khold_timer movlw K_press_st btfsc kstats,keypress movwf key_state return ;***** KEY TASK STATE MACHINE, PRESS STATE K_press incf khold_timer,f ; increment the keyhold timer movlw .76 xorwf khold_timer,w ; at 1.5 seconds goto push btfsc STATUS,Z goto K_pr_next ; goto next state is 1.5 seconds btfss kstats,keypress ; check for key release goto K_pr_open return K_pr_next movlw K_push_st movwf key_state return K_pr_open bsf kstats,press ; if open in press state then press command movlw K_Idle_st movwf key_state return ;***** KEY TASK STATE MACHINE, PUSH STATE K_push incf khold_timer,f ; increment the keyhold timer movlw .151 xorwf khold_timer,w ; at 3.0 seconds goto hold btfsc STATUS,Z goto K_pu_next ; goto next state is 1.5 seconds btfss kstats,keypress ; check for key release goto K_pu_open return K_pu_next movlw K_hold_st movwf key_state return K_pu_open bsf kstats,push ; if open in press state then press command movlw K_Idle_st movwf key_state return ;***** KEY TASK STATE MACHINE, HOLD STATE K_hold bsf kstats,hold ; generate first hold output btfss kstats,keypress ; check for key release goto K_hl_open movlw .150 movwf khold_timer movlw K_delay_st movwf key_state return K_hl_open movlw K_Idle_st ; at first key open return to idle movwf key_state return return ;***** KEY TASK STATE MACHINE, DELAY STATE K_delay decfsz khold_timer,f goto K_dly_k_chk K_dly_timout movlw K_hold_st movwf key_state return K_dly_k_chk btfsc kstats,keypress return movlw K_Idle_st movwf key_state return ;***** KEY TASK STATE MACHINE, DEFAULT STATE K_default bsf kstats,key_err return