M Author: AN594 Using the CCP Module(s) CCP OPERATION Mark Palmer Microchip Technology Inc. This application note discusses the operation of a Capture/Compare/PWM (CCP) module, and the interaction of multiple CCP modules with the timer resources. The (CCP) module is software programmable to operate in one of three modes: 1. 2. 3. A Capture input A Compare output A Pulse Width Modulation (PWM) output For the CCP module to function, Timer resources must be used in conjunction with the CCP module. The desired CCP mode of operation determines which timer resources are required. Table 1 shows the CCP mode with the corresponding timer resource required. Both the Capture and Compare modes require that Timer1 be operating in timer mode or synchronized counter mode. Note: Capture and Compare modes may not operate if Timer1 is operated in the asynchronous counter mode. TABLE 1: CCP MODE - TIMER RESOURCE CCP MODE Timer Resource Capture Timer1 Compare Timer1 PWM Timer2 The following three sections discuss the operation of the CCP module in each of its modes of operation. There is a simple example program for each mode of operation. The software example for the Capture mode, also uses a second CCP module in Compare mode to generate the signal to capture. PWM Mode A Pulse Width Modulation output (Figure 1) is a signal that has a time-base (period) and a time that the output stays high (duty cycle). The period is the duration after which the PWM rising edge repeats itself. The resolution of the PWM output is the granularity with which the duty cycle can be varied. The frequency of a PWM is simply the inverse of the period (1/ period). FIGURE 2: PWM MODE BLOCK DIAGRAM Duty cycle registers CCPxCON<5:4> CCPRxL CCPRxH (Slave) Q R Comparator RCy/CCPx TMR2 (Note 1) S TRISC<y> Comparator PR2 Clear Timer, CCPx pin and latch D.C. Note: 8-bit timer is concatenated with 2-bit internal Q clock or 2 bits of the prescaler to create 10-bit time-base. FIGURE 1: PWM OUTPUT Period Duty Cycle PWM frequency = 1/period TMR2 = PR2 TMR2 = PR2 TMR2 = CCPR1H 1997 Microchip Technology Inc. DS00594B-page 1 AN594 Appendix A is a program which generates up to a 10-bit PWM output. The PWM period and duty cycle are updated after the overflow of Timer1. Upon the overflow of Timer1, ports A, B and D are read. The 10-bit duty cycle is specified by the value on PORTB:PORTA<1:0>, while the period is specified by the value on PORTD. By setting the conditional assemble flag PICMaster to TRUE, these values are read from internal registers which are dummy registers for the ports (DUMMY_Px). This allows the software to be verified without the use of hardware and external stimulus. Each CCP module can support one Pulse Width Modulation (PWM) output signal, with minimal software overhead. This PWM signal can attain a resolution of up to 10-bits, from the 8-bit Timer2 module. This gives 1024 steps of variance from an 8-bit overflow counter. This gives a maximum accuracy of Tosc (50 ns, when the device is operated at 20 MHz). Figure 2 shows a block diagram of the CCP module in PWM mode. When the Timer2 overflows (timer = period register), the value in the duty cycle registers (CCPRxL:CCPRxCON<5:4>) is latched into the 10-bit slave latch. A new duty cycle value can be loaded into the duty cycle register(s) at any time, but is only latched into the slave latch when Timer2 = Timer2 Period Register (PR2). Since the PWM duty cycle is double buffered, the duty cycle registers are only loaded when there is sufficient time to complete the update of the 10-bit value before the Timer2 = PR2 match occurs. After the duty cycle has been updated and the Timer2 = PR2 match has occurred, the period (stored in the PR2 register) is updated. The operation of the CCP module in PWM mode is similar to the PIC17C42’s PWM. Additional concepts of PWM operation can be found in Application Notes AN564 and AN539. The period of Timer 2 (and PWM) is determined by the frequency of the device, the Timer2 prescaler value (1, 4 or 16), and the Timer2 Period Register. Equation 1 shows the calculation of the PWM period, duty cycle, and the minimum and maximum frequencies. EQUATION 1: PWM PERIOD, DUTY CYCLE, AND FREQUENCIES PWM Period = [(PR2) + 1] • 4 TOSC • (Timer 2 prescale value) PWM Duty Cycle = [CCPRxL:CCPRxCON<5:4>] • 4 TOSC • (Timer2 prescale value) PWM maximum frequency (High Resolution mode) = 4/(PR2 • TCY) (Low Resolution mode) = 1/(PR2 • TCY) PWM minimum frequency (High Resolution mode) = 4/(PR2 • TCY) (Low Resolution mode) = 1/(PR2 • TCY) Table 2 shows the minimum and maximum PWM frequency for different device frequencies. The Timer2 prescaler will be selected to give either the minimum or maximum frequencies as shown. TABLE 2: PWM FREQUENCY FOR DIFFERENT DEVICE FREQUENCIES 20 MHz 10 MHz 2 MHz PWM Resolution Min Max Min Max Min Max Units 10-bit 1.22 19.53 0.613 9.77 0.123 1.96 kHz 9-bit 1.22 39.06 0.613 9.77 0.123 3.92 kHz 10-bit 1.22 19.53 0.613 9.77 0.123 1.96 kHz 9-bit 1.22 39.06 0.613 9.77 0.123 3.92 kHz 10-bit 1.22 19.53 0.613 9.77 0.123 1.96 kHz 9-bit 1.22 39.06 0.613 9.77 0.123 3.92 kHz 10-bit 1.22 19.53 0.613 9.77 0.123 1.96 kHz 9-bit 1.22 39.06 0.613 9.77 0.123 3.92 kHz DS00594B-page 2 1997 Microchip Technology Inc. AN594 Compare Mode When the CCP module is in the OFF state (CCPxM3:CCPxM0 = 0h), the CCPx output latch is forced to a low level, though the level on the CCPx pin will be determined by the value in the data latch of the port. Figure 3 shows the block diagram of the CCP module in Compare mode. In Compare mode, the 16-bit value of Timer1 is compared to the CCPRxH:CCPRxL registers. When these registers match, the S/W configured event occurs on the CCPx pin. The events that can be S/W selected are: • • • • Appendix B is a program which uses the CCP module to transmit a pulse train dependent on the data byte. Timer1 is used as a free running timer, with each “new” compare value being an offset added to the present CCP compare latch value. The data is transmitted every 600 µs. Each data bit has a sync pulse (High level) of 8.8 µs. Then the data is transmitted as a low pulse. The time duration of the low pulse determines the value of the data bit. A ‘0’ bit is low for 18.8 µs while a ‘1’ bit is low for 37.6 µs. After the last data bit has been transmitted, another sync pulse is transmitted and the output remains low (idle time) until the 600 µs data period has completed. An example of the pulse train for the a data byte of 0x0CA is shown in Figure 4, and has an idle time of 224 µs. These pulse times are based off the device operational frequency. The program header file, COMP.H, calculates the values to be loaded into the compare registers from the specified Device_freq. The data to be transmitted is read from PORTB, during the idle time. By setting the conditional assemble flag PICMaster to TRUE, these values are read from internal registers which are dummy registers for the ports (DUMMY_Px). This allows the software to be verified without the use of hardware and external stimulus. Clear CCPx pin on match Set CCPx pin on match Generate S/W interrupt (CCPx pin unchanged) Trigger special event (CCPx pin unchanged) - CCP1 clears Timer1 - CCP2 clears Timer1 and sets the A/D’s GO/DONE bit The CCPxM3:CCPxM0 control bits, in register CCPxCON, configures the operation of the CCP module. The compare function must have the data direction of the CCPx pin configured as an output, if the compare event is to control the state of the CCPx pin. COMPARE MODE BLOCK DIAGRAM Trigger Special Event FIGURE 3: Q RCy/CCPx R TRISC<y> Output Enable FIGURE 4: S Set CCPxIF Interrupt PIR<b> CCPRxH CCPRxL Output Logic match Comparator TMR1H CCPxCON<3:0> Mode Select TMR1L TRANSMIT PULSE TRAIN (DATA = 0x0CA) CCPx Pin 1 1 1997 Microchip Technology Inc. 0 0 1 0 1 0 IDLE TIME DS00594B-page 3 AN594 Capture Mode In Capture mode, the 16-bit value of Timer1 is latched into the CCPRxH:CCPRxL registers, when the S/W configured event occurs on the CCPx pin. The events that can cause a capture are: • • • • Every falling edge Every rising edge Every 4th rising edge Every 16th rising edge The CCPxM3:CCPxM0 control bits, in register CCPxCON, configures the operation of the CCP module. The capture function works regardless of the data direction of the CCPx pin (input or output). With the CCPx pin is configured as an output, a write to the CCPx pin (in PORTC) will cause a capture when the capture requirement is met. FIGURE 5: CAPTURE MODE BLOCK DIAGRAM Set CCPxIF PIR<b> Prescaler 1, 4, 16 RCy/CCPx CCPRxH and edge detect Capture Enable TMR1H Q’s FIGURE 6: CCPRxL TMR1L CCPxCON<3:0> The changing of the Capture mode, via the CCPxM3:CCPxM0 bits, may cause the CCPxIF bit to be set. This “false” interrupt should be cleared (ignored) after changing between capture modes. The CCP prescaler is only cleared by configuring the CCP module into the OFF state (CCPxM3:CCPxM0 = 0h). Figure 5 shows the block diagram of the CCP module in Capture mode. The use of the CCP module in Capture mode is similar to the PIC17C42’s capture. Additional concepts of capture operation can be found in Application Note AN545. Appendix C is a program which implements a 16-bit capture from a free running timer (Timer1). The capture event is configured as each rising edge. The 16-bit capture value is the “new” 16-bit capture value minus the “old” 16-bit capture value. If the time between captures is greater than 216 Timer1 increments, an invalid result will occur. This invalid result is not indicated by the software. After the capture period result is calculated, the “new” capture value is loaded into the “old” register. The waveform that is captured is generated from a second CCP module in compare mode. The value that is loaded in to the CCPR2H:CCPR2L is read from the PORTB and PORTD registers. By setting the conditional assemble flag PICMaster to TRUE, these values are read from internal registers which are dummy registers for the ports (DUMMY_Px). This allows the software to be verified without the use of hardware and external stimulus. Figure 6 shows an input into the CCPx pin, and the capture measurement points. EXAMPLE CAPTURE WAVEFORM CCP1 Capture TMR1 Value Capture TMR1 Value Capture TMR1 Value PIC16CXXX DS00594B-page 4 1997 Microchip Technology Inc. AN594 INTERACTION OF CCP MODULES Due to the modularity of the PIC16CXXX peripherals, future devices with two or more CCP modules on a device are possible. Each CCP module operates independently from the others, though their interaction with the timer resources must be taken into account. When two or more CCP modules exist on a device, there can be an interaction between the CCP modules. This interaction is shown in Table 3. These interactions do NOT include any interaction (S/W) caused by the main program nor the interrupt service routines of the CCP sources. Interaction of Two Capture Modes When two CCP modules are in a Capture mode, Timer1 is the time-base for both captures. This means that they will have the same capture resolution, as determined by the Timer1 prescaler and frequency of the timer/counter clock. This clock can come from an external source (on the RC0/T1OSO/T1CKI pin), but must be synchronized to the device. TABLE 3: Interaction of One Capture Mode and One Compare Mode When one CCP module is in a Capture mode and a second CCP module is in Compare mode, Timer1 is the time-base for both the captures and the compare. This means that the capture and the compare will have the same resolution, as determined by the Timer1 prescaler and frequency of the timer/counter clock. This clock can come from an external source (on the RC0/T1OSO/T1CKI pin), but must be synchronized to the processor clock. Also, care must be taken in that the compare can be configured to clear TMR1 register (when in special Trigger mode). Care must be taken in system design to ensure that this clearing of the TMR1 register does not have any negative impact on the capture function. INTERACTION OF TWO CCP MODULES CCPx Mode CCPy Mode Interaction Capture Capture Same Timer1 time-base. Capture Capture The compare could be configured for trigger special event, which clears the TMR1 register. Capture Capture The compare(s) could be configured for trigger special event, which clears the TMR1 register. PWM PWM The PWMs will have the same frequency, and update rate (Timer2 interrupt). PWM Capture None PWM Capture None 1997 Microchip Technology Inc. DS00594B-page 5 AN594 EXAMPLE 1: ACTION TIMER1 STATE CCPR1H:CCPR1L = 0x0465 CCP1CON = 0x?B : : : CCPR2H:CCPR2L = 0x0165 CCP2CON = 0x?B : 0x???? 0x???? COMMENT CCP1 in Compare - Special Trigger Mode 0x0232 0x0333 0x0334 0x0465 0x0000 CCP2 in Compare - Special Trigger Mode CCP1 resets TMR1 and CCP1 Special Trigger function occurs 0x0165 0x0000 CCP2 resets TMR1 and CCP2 Special Trigger function occurs 0x0165 0x0000 CCP2 resets TMR1 and CCP2 Special Trigger function occurs : : : Interaction of Two Compare Modes CONCLUSION When two CCP modules are in a Compare mode, Timer1 is the time-base for both compares. This means that they will have the same compare resolution, as determined by the Timer1 prescaler and frequency of the timer/counter clock. This clock can come from an external source (on the RC0/T1OSO/T1CKI pin), but must be synchronized to the processor clock. Since the compare modules can be configured to clear TMR1 register (when in special Trigger mode), care must be taken in system design to ensure that this clearing of the TMR1 register does not have any negative impact on the compare function. If both compares are configured with a special trigger, which clears the TMR1 register, then the compare register that is closest to (but greater than) the TMR1 register value is the compare value that will reset the TMR1 register. Example 1 shows a possible case. The Capture/Compare/PWM modules offer enormous flexibility in the use of the device timer resources. As with all resources, care must be taken to ensure that no adverse system complications can occur with the interaction between multiple CCP modules. The programs for simple operation of the various CCP modes should be a good foundation for modifications to suite your particular needs. Interaction of Two PWM Modes When two CCP modules are in a PWM mode, Timer2 is the time-base for both PWM outputs. This means that they will have the same PWM frequency and update rates, as determined by the Timer2 prescaler and frequency of the device. The resolution of the two PWMs may be different, since each CCP module has its own CCPxX:CCPxY bits for high resolution mode. These bits are found in the CCPxCON<5:4> register. DS00594B-page 6 1997 Microchip Technology Inc. AN594 Please check the Microchip BBS for the latest version of the source code. Microchip’s Worldwide Web Address: www.microchip.com; Bulletin Board Support: MCHIPBBS using CompuServe® (CompuServe membership not required). APPENDIX A: PWM_1.ASM MPASM 01.40 Released LOC OBJECT CODE VALUE 00000000 00000001 00000001 00000001 00000001 0000 0000 1683 0001 188E PWM_1.ASM 1-16-1997 17:35:52 PAGE 1 LINE SOURCE TEXT 00001 00002 00003 00004 00005 00006 00007 00008 00009 00010 00011 00012 00013 00014 00015 00016 00017 00018 00019 00020 00021 00022 00023 00024 00025 00026 00027 00028 00029 00030 00031 00032 00033 00001 00002 00318 00034 00035 00036 00037 00038 00046 00047 00039 00040 00041 00042 00043 00044 00045 00046 00047 00048 00049 1997 Microchip Technology Inc. LIST P = 16C74, n = 66 ERRORLEVEL -302 ; ;******************************************************************* ; ; This program outputs a PWM signal on the CCP1 pin. The duty cycle and ; period of the PWM is read every time TMR1 overflows. ; PERIOD = PORTB ; DUTY CYCLE = PORTD and PORTE<1:0> ; ; The prescaler of TMR2 is selected by the state of PORTA<1:0> after ; reset RA1:RA0 Prescaler multiplies Tcyc by ; 0 0 1 ; 0 1 4 ; 1 x 16 ; ; ; Program = PWM_1.ASM ; Revision Date: 7-13-94 ; 1-16-97 Compatibility with MPASMWIN 1.40 ; ; ;********************************************************************* ; ; ; HARDWARE SETUP ; PORTA<1:0> - Prescaler to TMR2, read only after reset ; PORTB - Period of PWM ; PORTD - Duty Cycle high of PWM (8-bits) ; PORTE<1:0> - Duty Cycle low of PWM (2-bits) ; ; INCLUDE <p16c74.inc> LIST ; P16C74.INC Standard Header File, Ver. 1.00 Microchip Technology, Inc. LIST FALSE TRUE EQU EQU 0 1 INCLUDE <PWM.h> list ; PICMaster EQU TRUE Debug EQU TRUE Debug_PU EQU TRUE ; ; ; Reset address. Determine type ; org RESET_V RESET BSF STATUS, RP0 BTFSC PCON,NOT_POR ; A Debugging Flag ; A Debugging Flag ; A Debugging Flag of RESET ; RESET vector location ; Bank 1 ; Power-up reset? DS00594B-page 7 AN594 0002 2832 0003 285C 0004 0004 0004 0005 0006 0007 0007 0008 0009 1283 180C 280D 1505 1105 2807 000A 000A 1585 000B 1185 000C 280A 000D 000D 100C 000E 0853 000F 00D5 0010 0854 0011 00D6 0012 0851 0013 1683 0014 00A0 0015 1283 0016 0016 0017 0018 0019 001A 001B 001C 001D 001E 001F 0020 0021 0022 0023 0811 0212 390F 1903 2816 0855 0095 300F 0597 18D6 1697 1856 1617 108C 0024 0024 1C8C 0025 2824 DS00594B-page 8 00050 00051 00052 00053 00054 00055 00056 00057 00058 00059 00060 00061 00062 00063 00064 00065 00066 00067 00068 00069 00070 00071 00072 00073 00074 00075 00076 00077 00078 00079 00080 00081 00082 00083 00084 00085 00086 00087 00088 00089 00090 00091 00092 00093 00094 00095 00096 00097 00098 00099 00100 00101 00102 00103 00104 00105 00106 00107 00108 00109 00110 00111 00112 00113 00114 00115 GOTO GOTO START OTHER_RESET ; YES ; NO, a WDT or MCLR reset ; ; This is the Periperal Interrupt routine. Need to determine the type ; of interrupt that occurred. The following interrupts are enabled: ; 1. CCP Capture Occured ; page org ISR_V ; Interrupt vector location PER_INT_V BCF STATUS, RP0 ; Bank 0 BTFSC PIR1, TMR1IF ; TMR1 Overflow Interrupt occured? GOTO T1OVFL ; YES, Service the TMR1 Interrupt ERROR1 ; NO, Error Condition-Unknown Interrupt BSF PORTA, 2 ; Toggle a PORT pin BCF PORTA, 2 GOTO ERROR1 ; ERROR2 ; NO, Error Condition-Unknown Interrupt BSF PORTA, 3 ; Toggle a PORT pin BCF PORTA, 3 GOTO ERROR2 ; T1OVFL BCF PIR1, TMR1IF ; Clear T1 Overflow Interrupt Flag if (PICMaster ) MOVF DUMMY_PD, W ; else MOVF PORTD, W ; endif MOVWF DC_HI ; if (PICMaster ) MOVF DUMMY_PE, W ; else MOVF PORTE, W ; endif MOVWF DC_LO ; if (PICMaster ) MOVF DUMMY_PB, W ; else MOVF PORTB, W ; endif BSF STATUS, RP0 ; Bank 1 MOVWF T2_PERIOD ; BCF STATUS, RP0 ; Bank 0 ; WAIT_DC MOVF TMR2, W ; Read present TMR2 register value SUBWF PR2, W ; How close is the timer to rolling over ANDLW 0x0F ; Does this make it zero? BTFSC STATUS, Z ; If Z is set, near rollover GOTO WAIT_DC ; loop until rolled over MOVF DC_HI, W ; else losd the duty cycle values MOVWF CCPR1L ; Load DC high MOVLW 0x0F ; ANDWF CCP1CON, F ; Set the DC low bits BTFSC DC_LO, 1 ; BSF CCP1CON, CCP1X; BTFSC DC_LO, 0 ; BSF CCP1CON, CCP1Y; BCF PIR1, TMR2IF ; Clear the TRM2 = PR2 flag ; WAIT_PR BTFSS PIR1, TMR2IF ; LOOP waiting for TRM2 = PR2 GOTO WAIT_PR ; Need to wait until TMR2 = PR2 so that ; Duty Cycle is latched 1997 Microchip Technology Inc. AN594 0026 0027 0028 0029 002A 002B 002C 002D 002D 002E 002F 1683 300F 0092 30F0 0520 1903 2830 300F 0220 0792 0030 0030 1283 0031 0009 0032 0032 1283 0033 018F 0034 018E 0035 0035 0036 0037 0038 0039 003A 003B 003C 003D 0183 018B 018C 1683 3080 0081 018C 30FF 009F 003E 003F 0040 0041 0042 0043 1283 0185 0186 0187 0188 0189 0044 0045 0046 0047 0048 0049 004A 004B 004C 004D 1683 30FF 0085 0086 0187 0088 0089 0092 140C 1283 004E 300C 004F 0097 0050 018C 0051 0190 0052 0192 00116 00117 00118 00119 00120 00121 00122 00123 00124 00125 00126 00127 00128 00129 00130 00131 00132 00133 00134 00135 00136 00137 00138 00139 00140 00141 00142 00143 00144 00145 00146 00147 00148 00149 00150 00151 00152 00153 00154 00155 00156 00157 00158 00159 00160 00161 00162 00163 00164 00165 00166 00167 00168 00169 00170 00171 00172 00173 00174 00175 00176 00177 00178 00179 00180 00181 1997 Microchip Technology Inc. BSF MOVLW MOVWF MOVLW ANDWF BTFSC GOTO STATUS, RP0 0x0F PR2 0xF0 T2_PERIOD, W STATUS, Z NO_OFFSET ; ; ; ; ; ; ; Bank 1 Load TMR2 period with minimum value Fh MOVLW SUBWF ADDWF 0x0F ; Yes, calculate additional offset T2_PERIOD, W ; PR2, F ; ADD Period offset BCF RETFIE STATUS, RP0 Determine if period needs to be greater NO, Period is the minimum PR_OFFSET ; NO_OFFSET ; Bank 0 ; Return / Enable Global Interrupts ; page ; ;********************************************************************** ;***** Start program here, Power-On Reset occurred. ;********************************************************************** ; START ; POWER_ON Reset (Beginning of program) BCF STATUS, RP0 ; Bank 0 CLRF TMR1H ; CLRF TMR1L ; ; MCLR_RESET ; A Master Clear Reset CLRF STATUS ; Do initialization (Bank 0) CLRF INTCON CLRF PIR1 BSF STATUS, RP0 ; Bank 1 MOVLW 0x80 ; MOVWF OPTION_REG ; CLRF PIE1 ; Disable all peripheral interrupts MOVLW 0xFF ; MOVWF ADCON1 ; Port A is Digital. ; ; BCF STATUS, RP0 ; Bank 0 CLRF PORTA ; ALL PORT output should output Low. CLRF PORTB CLRF PORTC CLRF PORTD CLRF PORTE ; BSF STATUS, RP0 ; Select Bank 1 MOVLW 0xFF ; MOVWF TRISA ; RA5 - 0 inputs MOVWF TRISB ; RB7 - 0 inputs CLRF TRISC ; RC Port are outputs MOVWF TRISD ; RD Port are inputs MOVWF TRISE ; RE Port are inputs MOVWF PR2 ; Default PWM period BSF PIE1, TMR1IE ; Enable TMR1 Interrupt BCF STATUS, RP0 ; Select Bank 0 ; MOVLW 0X0C ; CCP module is in MOVWF CCP1CON ; PWM output mode ; ; Initialize the Special Function Registers (SFR) interrupts ; CLRF PIR1 ; CLRF T1CON ; CLRF T2CON ; if (PICMaster ) DS00594B-page 9 AN594 0053 1850 00182 00183 00184 00185 00186 00187 00188 00189 00190 00191 00192 00193 00194 00195 00196 00197 00198 00199 00200 00201 00202 00203 00204 00205 00206 00207 00208 00209 00210 00211 00212 00213 00214 00215 00216 00217 00218 00219 00220 0054 1412 0055 18D0 0056 1492 0057 0058 0059 005A 170B 178B 1410 1512 005B 285B 005C 1E03 005D 2807 005E 2832 005F 0000 07FF 07FF 2807 BTFSC DUMMY_PA, 0 ; PORTA, 0 ; T2CON, 0 ; else BTFSC endif BSF ; if (PICMaster ) BTFSC DUMMY_PA, 1 else BTFSC PORTA, 1 endif BSF T2CON, 1 ; ; ; ; BSF BSF BSF BSF INTCON, PEIE INTCON, GIE T1CON, TMR1ON T2CON, TMR2ON ; ; ; ; Enable Peripheral Interrupts Enable all Interrupts Turn Timer 1 ON Turn Timer 2 ON ; lzz goto lzz ; Loop waiting for TMR1 interrupt ; ; Here is where you do things depending on the type of RESET (Not a ; Power-On Reset). OTHER_RESET BTFSS STATUS,NOT_TO ; WDT Time-out? WDT_TIMEOUT GOTO ERROR1 ; YES, This is error condition if ( Debug_PU ) goto START ; MCLR reset, Goto START else GOTO MCLR_RESET ; MCLR reset, Goto MCLR_RESET endif ; if (Debug ) END_START NOP ; END label for debug endif ; ; org PMEM_END ; End of Program Memory GOTO ERROR1 ; If you get here your program was lost end _XT_OSC __16C74 lzz 00003FBD 00000001 0000005B MEMORY USAGE MAP (‘X’ = Used, ‘-’ = Unused) 0000 : XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX 0040 : XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX ---------------- ---------------07C0 : ---------------- ---------------- ---------------- ---------------X All other memory blocks unused. Program Memory Words Used: Program Memory Words Free: Errors : Warnings : Messages : 0 0 reported, 0 reported, DS00594B-page 10 97 3999 0 suppressed 17 suppressed 1997 Microchip Technology Inc. AN594 Please check the Microchip BBS for the latest version of the source code. Microchip’s Worldwide Web Address: www.microchip.com; Bulletin Board Support: MCHIPBBS using CompuServe® (CompuServe membership not required). APPENDIX B: PWM.H nolist ;****************************************************************************** ; ; This is the custom Header File for the real time clock application note ; PROGRAM:CLOCK.H ; Revision:7-13-94 ; ;****************************************************************************** ; This is used for the ASSEMBLER to recalculate certain frequency ; dependant variables. The value of Dev_Freq must be changed to ; reflect the frequency that the device actually operates at. ; Dev_Freq EQU D’10000000’; Device Frequency is 4 MHz PULSE_TIME EQU (( Dev_Freq / D’4000’ ) * D’188’ / D’10000’ ) ; DB_HI_BYTE LCD_INIT_DELAY INNER_CNTR OUTER_CNTR ; T1OSO ; RESET_V ISR_V PMEM_END TABLE_ADDR ; COUNTER ; XMIT_DATA DATA_CNT ONES_CNT CCP1_INT_CNT CCPREG_HI CCPREG_LO DUMMY_PA DUMMY_PB DUMMY_PC DUMMY_PD DUMMY_PE DC_HI DC_LO T2_PERIOD ; list EQU EQU EQU EQU (HIGH ((( Dev_Freq / 4 ) * 1 / D’1000’ ) / 3 ) ) + 1 (HIGH ((( Dev_Freq / 4 ) * D’46’ / D’10000’ ) / 3 ) ) + 1 40 ; RAM Location 41 ; RAM Location EQU 0 ; The RC0 / T1OSO / T1CKI EQU EQU EQU EQU 0x0000 0x0004 0x07FF 0x0400 ; ; ; ; EQU 0x021 EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU 0x30 0x31 0x32 0x33 0x40 0x41 0x50 0x51 0x52 0x53 0x54 0x55 0x56 0xA0 1997 Microchip Technology Inc. Address of RESET Vector Address of Interrupt Vector Last address in Program Memory Address where to start Tables ; DS00594B-page 11 AN594 Please check the Microchip BBS for the latest version of the source code. Microchip’s Worldwide Web Address: www.microchip.com; Bulletin Board Support: MCHIPBBS using CompuServe® (CompuServe membership not required). APPENDIX C: COMP_1.LST MPASM 01.40 Released LOC OBJECT CODE VALUE 00000000 00000001 00000001 00000001 00000001 0000 0000 0001 0002 0003 1683 188E 287C 28BA DS00594B-page 12 COMP_1.ASM 1-16-1997 17:35:21 PAGE 1 LINE SOURCE TEXT 00001 00002 00003 00004 00005 00006 00007 00008 00009 00010 00011 00012 00013 00014 00015 00016 00017 00018 00019 00020 00021 00022 00023 00024 00025 00026 00027 00028 00029 00030 00031 00001 00002 00318 00032 00033 00034 00035 00036 00052 00053 00037 00038 00039 00040 00041 00042 00043 00044 00045 00046 00047 00048 00049 LIST P = 16C74, n = 66 ERRORLEVEL -302 ; ;******************************************************************** ; ; This program outputs a pulse train on the CCP1 pin, as specified by ; the values in the CCPR1H:CCPR1L. ; ; ____ ____ __ ; Pulse Train ___| |________| |____| ; Data Value <---- 1 ----> <-- 0 --> ; ^ ^ ^ ^ ; | | | | ; | T_ONE_BIT | T_ZERO_BIT ; | | ; PULSE_TIME PULSE_TIME ; ; ; Program = COMP_1.ASM ; Revision Date: 7-13-94 ; 1-16-97 Compatibility with MPASMWIN 1.40 ; ; ;********************************************************************* ; ; ; HARDWARE SETUP ; PORTB - Data to serial transmit on CCP pin ; ; INCLUDE <p16c74.inc> LIST ;P16C74.INC Standard Header File, Version 1.00 Microchip Technology LIST FALSE TRUE EQU EQU 0 1 INCLUDE <COMP.h> list ; PICMaster EQU TRUE ; A Debugging Flag Debug EQU TRUE ; A Debugging Flag Debug_PU EQU TRUE ; A Debugging Flag ; ; ; Reset address. Determine type of RESET ; org RESET_V ; RESET vector location RESET BSF STATUS, RP0 ; Bank 1 BTFSC PCON,NOT_POR ; Power-up reset? GOTO START ; YES GOTO OTHER_RESET ; NO, a WDT or MCLR reset 1997 Microchip Technology Inc. AN594 0004 0004 0004 1405 0005 0006 0007 0008 0008 0009 000A 1283 190C 280E 1505 1105 2808 000B 000B 1585 000C 1185 000D 280B 000E 000E 000F 0010 0011 0012 0012 0013 0014 0015 0016 0017 0018 0018 0019 001A 001B 001C 001D 001E 001F 001F 0020 0021 0022 0023 0024 110C 0AB3 1C33 2833 03B1 1903 2827 0DB0 1803 281F 302F 0795 1803 0A96 3000 0796 287A 305E 0795 1803 0A96 3000 0796 00050 00051 00052 00053 00054 00055 00056 00057 00058 00059 00060 00061 00062 00063 00064 00065 00066 00067 00068 00069 00070 00071 00072 00073 00074 00075 00076 00077 00078 00079 00080 00081 00082 00083 00084 00085 00086 00087 00088 00089 00090 00091 00092 00093 00094 00095 00096 00097 00098 00099 00100 00101 00102 00103 00104 00105 00106 00107 00108 00109 00110 00111 00112 00113 00114 00115 ; ; This is the Periperal Interrupt routine. Need to determine the type ; of interrupt that occurred. The following interrupts are enabled: ; 1. CCP Capture Occured ; page org ISR_V ; Interrupt vector location PER_INT_V if ( Debug ) bsf PORTA, 0 ; Turn on strobe endif ; BCF STATUS, RP0 ; Bank 0 BTFSC PIR1, CCP1IF ; Compare Interrupt occured? GOTO CCP1_INT ; YES, Service the TMR1 Interrupt ERROR1 ; NO, Error Condition-Unknown Interrupt BSF PORTA, 2 ; Toggle a PORT pin BCF PORTA, 2 GOTO ERROR1 ; ERROR2 ; NO, Error Condition-Unknown Interrupt BSF PORTA, 3 ; Toggle a PORT pin BCF PORTA, 3 GOTO ERROR2 ; ; ;********************************************************************* ; In the CCP interrupt. ; Since timer1 is not cleared on a CCP match, the value in the ; CCPR1H:CCPR1L register pair must be updated. This is done with ; a 16-bit add. Also after the 1st CCP1 match (CCP1 pin goes high) the ; next match will force it low. Depending on the value of the data bit ; determines the value add to the CCPR1H:CCPR1L register pair. ; ; After the data has been transmitted, the pin will have a sync pulse ; and then remain low for 300 us. ;********************************************************************** ; CCP1_INT BCF INCF BTFSS GOTO PIR1, CCP1IF ; Clear CCP1 Interrupt Flag CCP1_INT_CNT, F ; CCP1_INT_CNT, 0 ; SYNC_PULSE DECF BTFSC GOTO RLF BTFSC GOTO DATA_CNT, F STATUS, Z PERIOD_DELTA XMIT_DATA, F STATUS, C ONE_DATA MOVLW ADDWF BTFSC INCF MOVLW ADDWF GOTO LOW ( T_ZERO_BIT ) ; NO, Stay low for 8.8 us CCPR1L, F ; Update Compare register pair latch STATUS, C ; CCPR1H, F ; HIGH (T_ZERO_BIT ) ; CCPR1H, F ; RET_FIE MOVLW ADDWF BTFSC INCF MOVLW ADDWF LOW ( T_ONE_BIT ) CCPR1L, F STATUS, C CCPR1H, F HIGH ( T_ONE_BIT ) CCPR1H, F DATA_PULSE ; ; ; ; ; ; Decrement the Count of data bits Have we transmitted all the Data Bits? YES, Delay to 300 us NO, get next bit to transmit Is the bit to transmit a ‘1’? YES, Stay low for 17.6 us ZERO_DATA ; ONE_DATA 1997 Microchip Technology Inc. ; Stay low for 17.6 us ; Update Compare register pair latch ; ; ; ; DS00594B-page 13 AN594 0025 0AB2 0026 287A 0027 0027 0028 0029 002A 002B 002C 002D 002E 002F 0030 0031 0032 0033 0033 0034 0035 0036 0037 0038 0039 003A 003B 003B 003C 003D 003E 003F 0040 0041 0042 0042 0043 0044 0045 0046 0047 0048 0049 0049 004A 004B 004C 004D 004E 004F 0050 0050 0051 0052 0053 0054 0055 0056 0832 390F 0782 283B 2842 2849 2850 2857 285E 2865 286C 2873 302F 0795 1803 0A96 3000 0796 1417 0009 30EC 0795 1803 0A96 3002 0796 287A 30BD 0795 1803 0A96 3002 0796 287A 308E 0795 1803 0A96 3002 0796 287A 305F 0795 1803 0A96 3002 0796 287A 0057 0057 3030 0058 0795 00116 00117 00118 00119 00120 00121 00122 00123 00124 00125 00126 00127 00128 00129 00130 00131 00132 00133 00134 00135 00136 00137 00138 00139 00140 00141 00142 00143 00144 00145 00146 00147 00148 00149 00150 00151 00152 00153 00154 00155 00156 00157 00158 00159 00160 00161 00162 00163 00164 00165 00166 00167 00168 00169 00170 00171 00172 00173 00174 00175 00176 00177 00178 00179 00180 00181 DS00594B-page 14 INCF GOTO ONES_CNT, F RET_FIE ; Increment the number of 1’s in the byte MOVF ANDLW ADDWF GOTO GOTO GOTO GOTO GOTO GOTO GOTO GOTO GOTO ONES_CNT, W 0x0F PCL, F ZERO_1 ONE_1 TWO_1 THREE_1 FOUR_1 FIVE_1 SIX_1 SEVEN_1 EIGHT_1 ; ; ; ; ; ; ; ; ; ; ; ; MOVLW ADDWF BTFSC INCF MOVLW ADDWF BSF RETFIE LOW ( PULSE_TIME ) ;Update Compare register pair latch CCPR1L, F ; STATUS, C ; CCPR1H, F ; HIGH ( PULSE_TIME ); CCPR1H, F ; CCP1CON, 0 ; On Compare match, CCP1 pin = L MOVLW ADDWF BTFSC INCF MOVLW ADDWF GOTO LOW ( ZERO_1S ) CCPR1L, F STATUS, C CCPR1H, F HIGH ( ZERO_1S ) CCPR1H, F RET_FIE ; Update Compare register pair latch ; ; ; ; ; MOVLW ADDWF BTFSC INCF MOVLW ADDWF GOTO LOW ( ONE_1S ) CCPR1L, F STATUS, C CCPR1H, F HIGH ( ONE_1S ) CCPR1H, F RET_FIE ; Update Compare register pair latch ; ; ; ; ; MOVLW ADDWF BTFSC INCF MOVLW ADDWF GOTO LOW ( TWO_1S ) CCPR1L, F STATUS, C CCPR1H, F HIGH ( TWO_1S ) CCPR1H, F RET_FIE ; Update Compare register pair latch ; ; ; ; ; MOVLW ADDWF BTFSC INCF MOVLW ADDWF GOTO LOW ( THREE_1S ) CCPR1L, F STATUS, C CCPR1H, F HIGH ( THREE_1S ) CCPR1H, F RET_FIE ; Update Compare register pair latch ; ; ; ; ; MOVLW ADDWF LOW ( FOUR_1S ) CCPR1L, F ; Update Compare register pair latch ; ; PERIOD_DELTA Only want 9 states (0 1s to 8 1s) There There There There There There There There There was was was was was was was was was 0 1 2 3 4 5 6 7 8 ones in the data byte one in the data byte ones in the data byte ones in the data byte ones in the data byte ones in the data byte ones in the data byte ones in the data byte ones in the data byte ; SYNC_PULSE ; ZERO_1 ; ONE_1 ; TWO_1 ; THREE_1 ; FOUR_1 1997 Microchip Technology Inc. AN594 0059 005A 005B 005C 005D 005E 005E 005F 0060 0061 0062 0063 0064 0065 0065 0066 0067 0068 0069 006A 006B 006C 006C 006D 006E 006F 0070 0071 0072 0073 0073 0074 0075 0076 0077 0078 0079 1803 0A96 3002 0796 287A 3001 0795 1803 0A96 3002 0796 287A 30D2 0795 1803 0A96 3001 0796 287A 30A3 0795 1803 0A96 3001 0796 287A 3074 0795 1803 0A96 3001 0796 287A 007A 007A 1017 007B 0009 007C 007C 1283 007D 018F 007E 018E 007F 007F 0080 0081 0082 0083 0084 0085 0086 1283 0183 018B 018C 1683 3080 0081 018C 00182 00183 00184 00185 00186 00187 00188 00189 00190 00191 00192 00193 00194 00195 00196 00197 00198 00199 00200 00201 00202 00203 00204 00205 00206 00207 00208 00209 00210 00211 00212 00213 00214 00215 00216 00217 00218 00219 00220 00221 00222 00223 00224 00225 00226 00227 00228 00229 00230 00231 00232 00233 00234 00235 00236 00237 00238 00239 00240 00241 00242 00243 00244 00245 00246 00247 BTFSC INCF MOVLW ADDWF GOTO STATUS, C ; CCPR1H, F ; HIGH ( FOUR_1S ); CCPR1H, F ; RET_FIE MOVLW ADDWF BTFSC INCF MOVLW ADDWF GOTO LOW ( FIVE_1S ) CCPR1L, F STATUS, C CCPR1H, F HIGH ( FIVE_1S CCPR1H, F RET_FIE ; Update Compare register pair latch ; ; ; ; ; MOVLW ADDWF BTFSC INCF MOVLW ADDWF GOTO LOW ( SIX_1S ) CCPR1L, F STATUS, C CCPR1H, F HIGH ( SIX_1S ) CCPR1H, F RET_FIE ; Update Compare register pair latch ; ; ; ; ; MOVLW ADDWF BTFSC INCF MOVLW ADDWF GOTO LOW ( SEVEN_1S ) CCPR1L, F STATUS, C CCPR1H, F HIGH ( SEVEN_1S ) CCPR1H, F RET_FIE ; Update Compare register pair latch ; ; ; ; ; MOVLW ADDWF BTFSC INCF MOVLW ADDWF GOTO LOW ( EIGHT_1S ) CCPR1L, F STATUS, C CCPR1H, F HIGH ( EIGHT_1S ) CCPR1H, F RET_FIE ; Update Compare register pair latch ; ; ; ; ; BCF RETFIE CCP1CON, 0 ; On Compare match, CCP1 pin = H ; Return / Enable Global Interrupts ; FIVE_1 ; SIX_1 ; SEVEN_1 ; EIGHT_1 RET_FIE ; page ; ;********************************************************************** ;***** Start program here, Power-On Reset occurred. ;********************************************************************** ; START ; POWER_ON Reset (Beginning of program) BCF STATUS, RP0 ; Bank 0 CLRF TMR1H ; CLRF TMR1L ; ; MCLR_RESET ; A Master Clear Reset BCF STATUS, RP0 ; Bank 0 CLRF STATUS ; Do initialization (Bank 0) CLRF INTCON CLRF PIR1 BSF STATUS, RP0 ; Bank 1 MOVLW 0x80 ; Disable PORTB weak pull-ups MOVWF OPTION_REG ; CLRF PIE1 ; Disable all peripheral interrupts 1997 Microchip Technology Inc. DS00594B-page 15 AN594 0087 30FF 0088 009F 0089 008A 008B 008C 008D 008E 008F 0090 0091 0092 0093 0094 0095 0096 0097 0098 1283 0185 0186 0187 0188 0189 1010 1683 0185 30FF 0086 0187 0188 0189 150C 1283 0099 009A 009B 009C 018C 0190 170B 178B 009D 009E 009F 00A0 00A1 00A2 00A3 00A4 00A5 00A6 00A7 00A8 00A9 00AA 00AB 00AC 1010 3041 008F 3042 008E 038E 1803 038F 3008 0097 3009 00B1 01B2 30FF 00B3 1410 00AD 00AD 00AE 00AF 00B0 0831 1D03 28AD 0000 00B1 1005 DS00594B-page 16 00248 00249 00250 00251 00252 00253 00254 00255 00256 00257 00258 00259 00260 00261 00262 00263 00264 00265 00266 00267 00268 00269 00270 00271 00272 00273 00274 00275 00276 00277 00278 00279 00280 00281 00282 00283 00284 00285 00286 00287 00288 00289 00290 00291 00292 00293 00294 00295 00296 00297 00298 00299 00300 00301 00302 00303 00304 00305 00306 00307 00308 00309 00310 00311 00312 00313 MOVLW MOVWF 0xFF ADCON1 ; ; Port A is Digital. BCF CLRF CLRF CLRF CLRF CLRF BCF STATUS, RP0 PORTA PORTB PORTC PORTD PORTE T1CON, TMR1ON ; Bank 0 ; ALL PORT output should output Low. BSF CLRF MOVLW MOVWF CLRF CLRF CLRF BSF BCF STATUS, RP0 TRISA 0xFF TRISB TRISC TRISD TRISE PIE1, CCP1IE STATUS, RP0 ; ; ; ; ; ; ; ; ; ; ; ; Timer 1 is NOT incrementing ; Select Bank 1 RA5 - 0 outputs RB Port are RC Port are RD Port are RE Port are Enable CCP1 Select Bank inputs outputs outputs outputs Interrupt 0 ; page ; ; ; Initialize the Special Function Registers (SFR) interrupts ; CLRF PIR1 ; CLRF T1CON ; Timer mode BSF INTCON, PEIE ; Enable Peripheral Interrupts BSF INTCON, GIE ; Enable all Interrupts ; ; Set-up timer and compare latches and then turn timer1 on. ; BCF T1CON, TMR1ON ; Turn OFF timer1 MOVLW CCPREG_HI ; TMR1 = CCPR1H:CCPR1L - 1 MOVWF TMR1H ; MOVLW CCPREG_LO ; MOVWF TMR1L ; DECF TMR1L, F ; BTFSC STATUS, C ; DECF TMR1H, F ; MOVLW 0x08 ; On match CCP1 = H level MOVWF CCP1CON ; MOVLW 0x09 ; MOVWF DATA_CNT ; 8-bits to transfer CLRF ONES_CNT ; Result after xmit holds the number MOVLW 0xFF ; of 1’s in a byte MOVWF CCP1_INT_CNT ; No CCP1 transmit interrups yet BSF T1CON, TMR1ON ; Turn ON timer1 ; ; ; This code segment is an infinite loop that will always transmit the data ; contained in the XMIT_DATA register. After each byte is transmitted a ; new byte is read. If using PICMASTER (in stand alone mode), this is ; read from a register that is updated after a break (at NOP). If in a ; system, PORTB is read. All other variables are reinitalized after each ; byte. NEXT_BYTE ; WAIT MOVF DATA_CNT, w ; BTFSS STATUS, Z ; Is DATA_CNT = 0 ? GOTO WAIT ; NO, must wait until YES NOP ; if ( Debug ) bcf PORTA, 0 ; Turn off strobe 1997 Microchip Technology Inc. AN594 00B2 00B3 00B4 00B5 00B6 00B7 00B8 00B9 00BA 00BB 00BC 00BD 07FF 07FF 0000 0040 0080 07C0 00314 endif ; 00315 00316 if ( PICMaster ) 0840 00317 MOVF DUMMY_PB, W ; 00318 else 00319 MOVF PORTB, W ; 00320 endif 00B0 00321 MOVWF XMIT_DATA ; New data to transmit 30FF 00322 MOVLW 0xFF ; 00B3 00323 MOVWF CCP1_INT_CNT ; 3009 00324 MOVLW 0x09 ; 00B1 00325 MOVWF DATA_CNT ; 01B2 00326 CLRF ONES_CNT ; 28AD 00327 GOTO NEXT_BYTE ; 00328 ; 00329 ; 00330 ; Here is where you do things depending on the type of RESET (Not a 00331 ; Power-On Reset). 1E03 00332 OTHER_RESET BTFSS STATUS,NOT_TO ; WDT Time-out? 2808 00333 WDT_TIMEOUT GOTO ERROR1 ; YES, This is error condition 00334 if ( Debug_PU ) 287C 00335 goto START ; MCLR reset, Goto START 00336 else 00337 GOTO MCLR_RESET ; MCLR reset, Goto MCLR_RESET 00338 endif 00339 ; 00340 if (Debug ) 0000 00341 END_START NOP ; END label for debug 00342 endif 00343 ; 00344 ; 00345 org PMEM_END ; End of Program Memory 2808 00346 GOTO ERROR1 ; If you get here your program was lost 00347 00348 end : XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX : XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX : XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX XXXXXXXXXXXXXX-: ---------------- ---------------- ---------------- ---------------X All other memory blocks unused. Program Memory Program Memory Errors : Warnings : Messages : Words Used: Words Free: 0 0 reported, 0 reported, 1997 Microchip Technology Inc. 191 3905 0 suppressed 10 suppressed DS00594B-page 17 AN594 Please check the Microchip BBS for the latest version of the source code. Microchip’s Worldwide Web Address: www.microchip.com; Bulletin Board Support: MCHIPBBS using CompuServe® (CompuServe membership not required). APPENDIX D: nolist ;****************************************************************************** ; ; This is the custom Header File for the real time clock application note ; PROGRAM:CLOCK.H ; Revision:7-13-94 ; ;****************************************************************************** ; This is used for the ASSEMBLER to recalculate certain frequency ; dependant variables. The value of Dev_Freq must be changed to ; reflect the frequency that the device actually operates at. ; Dev_Freq EQU D’10000000’; Device Frequency is 10 MHz PULSE_TIME EQU (( Dev_Freq / D’4000’ ) * D’188’ / D’10000’ ) T_ZERO_BIT EQU (( Dev_Freq / D’4000’ ) * D’188’ / D’10000’ ) T_ONE_BIT EQU (( Dev_Freq / D’4000’ ) * D’376’ / D’10000’ ) ; ZERO_1S EQU ((( Dev_Freq / D’4000’ ) * (D’6000’ - (D’16’ * D’188’))) / D’10000’ ) ONE_1S EQU ( ( Dev_Freq / D’4000’ ) * (D’6000’ - (3 * D’188’ + D’14’ * D’188’)) / D’10000’) TWO_1S EQU ( ( Dev_Freq / D’4000’ ) * (D’6000’ - (6 * D’188’ + D’12’ * D’188’)) / D’10000’) THREE_1S EQU ( ( Dev_Freq / D’4000’ ) * (D’6000’ - (D’9’ * D’188’ + D’10’ * D’188’)) / D’10000’) FOUR_1S EQU ( ( Dev_Freq / D’4000’ ) * (D’6000’ - (D’12’ * D’188’ + 8 * D’188’)) / D’10000’) FIVE_1S EQU ( ( Dev_Freq / D’4000’ ) * (D’6000’ - (D’15’ * D’188’ + 6 * D’188’)) / D’10000’) SIX_1S EQU ( ( Dev_Freq / D’4000’ ) * (D’6000’ - (D’18’ * D’188’ + 4 * D’188’)) / D’10000’) SEVEN_1S EQU ( ( Dev_Freq / D’4000’ ) * (D’6000’ - (D’21’ * D’188’ + 2 * D’188’)) / D’10000’) EIGHT_1S EQU ( ( Dev_Freq / D’4000’ ) * (D’6000’ - (D’24’ * D’188’) ) / D’10000’ ) DB_HI_BYTE EQU (HIGH ((( Dev_Freq / 4 ) * 1 / D’1000’ ) / 3 ) ) + 1 LCD_INIT_DELAY EQU (HIGH ((( Dev_Freq / 4 ) * D’46’ / D’10000’ ) / 3 ) ) + 1 INNER_CNTR EQU 40 ; RAM Location OUTER_CNTR EQU 41 ; RAM Location ; T1OSO EQU 0 ; The RC0 / T1OSO / T1CKI ; RESET_V EQU 0x0000 ; Address of RESET Vector ISR_V EQU 0x0004 ; Address of Interrupt Vector PMEM_END EQU 0x07FF ; Last address in Program Memory TABLE_ADDR EQU 0x0400 ; Address where to start Tables ; COUNTER EQU 0x021 ; ; XMIT_DATA EQU 0x30 DATA_CNT EQU 0x31 ONES_CNT EQU 0x32 CCP1_INT_CNT EQU 0x33 DUMMY_PB EQU 0x40 CCPREG_HI EQU 0x41 CCPREG_LO EQU 0x42 ; list DS00594B-page 18 1997 Microchip Technology Inc. AN594 Please check the Microchip BBS for the latest version of the source code. Microchip’s Worldwide Web Address: www.microchip.com; Bulletin Board Support: MCHIPBBS using CompuServe® (CompuServe membership not required). APPENDIX E: MPASM 01.40 Released LOC OBJECT CODE VALUE CAPT_2.ASM 00000000 00000001 00000001 00000001 00000001 0000 0000 0001 0002 0003 1683 188E 282F 2861 1-16-1997 17:34:47 PAGE 1 LINE SOURCE TEXT 00001 00002 00003 00004 00005 00006 00007 00008 00009 00010 00011 00012 00013 00014 00015 00016 00017 00018 00019 00020 00021 00022 00023 00024 00001 00002 00318 00025 00026 00027 00028 00029 00052 00030 00031 00032 00033 00034 00035 00036 00037 00038 00039 00040 00041 00042 00043 00044 00045 00046 00047 00048 00049 00050 LIST P = 16C74, n = 66 ERRORLEVEL -302 ; ;******************************************************************** ; ; This program implements a real time clock using the TMR1 module of the ; PIC16CXXX family. ; ; Program = CAPT_2.ASM ; Revision Date: 7-19-94 ; 1-16-97 Compatibility with MPASMWIN 1.40 ; ; ;******************************************************************* ; ; ; HARDWARE SETUP ; ; CCP2 Compare Output ; CCP1 Capture Input ; CCP2 ---> CCP1 ; ; INCLUDE <p16c74.inc> LIST ; P16C74.INC Standard Header File, Ver. 1.00 Microchip Technology, Inc. LIST FALSE TRUE EQU EQU 0 1 INCLUDE <CAPT.h> list ; ; PICMaster EQU TRUE ; A Debugging Flag Debug EQU TRUE ; A Debugging Flag Debug_PU EQU TRUE ; A Debugging Flag ; ; ; Reset address. Determine type of RESET ; org RESET_V ; RESET vector location RESET BSF STATUS, RP0 ; Bank 1 BTFSC PCON,NOT_POR ; Power-up reset? GOTO START ; YES GOTO OTHER_RESET ; NO, a WDT or MCLR reset ; ; This is the Periperal Interrupt routine. Need to determine the type ; of interrupt that occurred. The following interrupts are enabled: ; 1. CCP1 Capture Occurred ; 2. CCP2 Compare Occurred ; page 1997 Microchip Technology Inc. DS00594B-page 19 AN594 0004 0004 0004 0005 0006 0007 0008 0009 000A 000B 000B 000C 000D 1283 190C 281D 180D 2811 180C 282D 1488 1088 280B 000E 000E 1508 000F 1108 0010 280E 0011 0011 100D 0012 0851 0013 079B 0014 1803 0015 0A9C 0016 0853 0017 0018 0019 001A 001B 001C 001C 079C 0AB3 141D 1C33 101D 0009 001D 001D 001E 001F 0020 0021 110C 0815 00C1 0816 00C0 0022 0023 0024 0025 0026 0027 0028 0843 02C1 1C03 03C0 0842 02C0 0815 DS00594B-page 20 00051 00052 00053 00054 00055 00056 00057 00058 00059 00060 00061 00062 00063 00064 00065 00066 00067 00068 00069 00070 00071 00072 00073 00074 00075 00076 00077 00078 00079 00080 00081 00082 00083 00084 00085 00086 00087 00088 00089 00090 00091 00092 00093 00094 00095 00096 00097 00098 00099 00100 00101 00102 00103 00104 00105 00106 00107 00108 00109 00110 00111 00112 00113 00114 00115 00116 org PER_INT_V ISR_V BCF BTFSC GOTO BTFSC GOTO BTFSC GOTO STATUS, RP0 PIR1, CCP1IF CAPTURE PIR2, CCP2IF COMPARE PIR1, TMR1IF T1OVFL BSF BCF GOTO PORTD, 1 PORTD, 1 ERROR1 BSF BCF GOTO PORTD, 2 PORTD, 2 ERROR2 ERROR1 ; ERROR2 ; Interrupt vector location ; ; ; ; ; ; ; ; ; Bank 0 CCP1 Interrupt occurred? (Capture) YES, Service the CCP1 Interrupt CCP2 Interrupt occurred? (Compare) YES, Service the CCP2 Interrupt NO, Timer 1 Overflow? YES, NO, Error Condition-Unknown Interrupt Toggle a PORT pin ; NO, Error Condition-Unknown Interrupt ; Toggle a PORT pin ; ; The Compare generates a Square wave based on the value on PORTB (in ; DUMMY_PB) and on PORTD (in DUMMY_PD). PORTB is loaded into low compare ; latch and PORTD is loaded into the high compare latch. If the value of ; the ports is not changed, a capture overflow condition will occur when ; PORTD:PORTB > 7Fh. This overflow is only indicated by the time between ; captures being much less then expected. COMPARE BCF PIR2, CCP2IF ; Clear CCP2 Interrupt Flag if ( PICMaster ) MOVF DUMMY_PB, W ; else MOVF PORTB, W ; endif ADDWF CCPR2L, F ; Update Compare register pair latch BTFSC STATUS, C ; INCF CCPR2H, F ; if ( PICMaster ) MOVF DUMMY_PD, W ; else MOVF PORTD, W ; endif ADDWF CCPR2H, F ; INCF CCP2_INT_CNT, F ; BSF CCP2CON, 0 ; On Compare match, CCP2 pin = L BTFSS CCP2_INT_CNT, 0 ; BCF CCP2CON, 0 ; On Compare match, CCP2 pin = H END_COMPARE RETFIE ; Return / Enable Global Interrupts ; ; The result of the new capture minus the old capture is stored in the ; new capture registers (CAPT_NEW_H:CAPT_NEW_L) ; CAPTURE BCF PIR1, CCP1IF ; Clear CCP1 Interrupt Flag MOVF CCPR1L, W ; New capture value (low byte) MOVWF CAPT_NEW_L ; MOVF CCPR1H, W ; New capture value (high byte) MOVWF CAPT_NEW_H ; ; MOVF CAPT_OLD_L, W ; SUBWF CAPT_NEW_L, F ; Subtract the low bytes of the 2 captures BTFSS STATUS, C ; Did a borrow occur? DECF CAPT_NEW_H, F ; YES, Decrement old capture (high byte) MOVF CAPT_OLD_H, W ; New capture value (low byte) SUBWF CAPT_NEW_H, F ; Subtract the low bytes of the 2 captures LOAD_OLD MOVF CCPR1L, W ; New capture value (low byte) 1997 Microchip Technology Inc. AN594 0029 002A 002B 002C 002C 00C3 0816 00C2 0009 002D 002D 100C 002E 0009 002F 002F 1283 0030 018F 0031 018E 0032 0032 0033 0034 0035 0036 0037 0038 0039 003A 003B 003C 1283 0183 018B 018C 1683 3000 0081 018C 018D 30FF 009F 003D 003E 003F 0040 0041 0042 0043 1283 0185 0186 0187 0188 0189 1010 0044 0045 0046 0047 0048 0049 004A 004B 004C 004D 004E 1683 0185 30FF 0086 0187 1507 0088 0189 150C 140D 1283 004F 0050 0051 0052 0053 018C 018D 0190 170B 178B 00117 00118 00119 00120 00121 00122 00123 00124 00125 00126 00127 00128 00129 00130 00131 00132 00133 00134 00135 00136 00137 00138 00139 00140 00141 00142 00143 00144 00145 00146 00147 00148 00149 00150 00151 00152 00153 00154 00155 00156 00157 00158 00159 00160 00161 00162 00163 00164 00165 00166 00167 00168 00169 00170 00171 00172 00173 00174 00175 00176 00177 00178 00179 00180 00181 00182 MOVWF CAPT_OLD_L ; MOVF CCPR1H, W ; New capture value (high byte) MOVWF CAPT_OLD_H ; END_CAPTURE RETFIE ; ; T1OVFL BCF PIR1, TMR1IF ; Clear T1 Overflow Interrupt Flag RETFIE ; Return / Enable Global Interrupts ; ; ;*********************************************************************** ;***** Start program here, Power-On Reset occurred. ;*********************************************************************** ; START ; POWER_ON Reset (Beginning of program) BCF STATUS, RP0 ; Bank 0 CLRF TMR1H ; CLRF TMR1L ; ; MCLR_RESET ; A Master Clear Reset BCF STATUS, RP0 ; Bank 0 CLRF STATUS ; Do initialization (Bank 0) CLRF INTCON CLRF PIR1 BSF STATUS, RP0 ; Bank 1 MOVLW 0x00 ; The LCD module does not like to work w/ MOVWF OPTION_REG ; weak pull-ups CLRF PIE1 ; Disable all peripheral interrupts CLRF PIE2 ; Disable all peripheral interrupts MOVLW 0xFF ; MOVWF ADCON1 ; Port A is Digital. ; ; BCF STATUS, RP0 ; Bank 0 CLRF PORTA ; ALL PORT output should output Low. CLRF PORTB CLRF PORTC CLRF PORTD CLRF PORTE BCF T1CON, TMR1ON ; Timer 1 is NOT incrementing ; BSF STATUS, RP0 ; Select Bank 1 CLRF TRISA ; RA5 - 0 outputs MOVLW 0xFF ; MOVWF TRISB ; RB7 - 0 inputs CLRF TRISC ; RC Port are outputs BSF TRISC, 2 ; CCP1 is an INPUT MOVWF TRISD ; RD Port are inputs CLRF TRISE ; RE Port are outputs BSF PIE1, CCP1IE ; Enable CCP1 Interrupt BSF PIE2, CCP2IE ; Enable CCP2 Interrupt BCF STATUS, RP0 ; Select Bank 0 ; ; ; Initialize the Special Function Registers (SFR) interrupts ; CLRF PIR1 ; CLRF PIR2 ; CLRF T1CON ; Timer mode BSF INTCON, PEIE ; Enable Peripheral Interrupts BSF INTCON, GIE ; Enable all Interrupts ; ; Set-up timer and compare latches and then turn timer1 on. ; 1997 Microchip Technology Inc. DS00594B-page 21 AN594 0054 1010 0055 0056 0057 0058 0059 005A 005B 005C 005D 005E 005F 0060 0061 0062 0063 0064 07FF 07FF 0000 0040 07C0 00183 BCF T1CON, TMR1ON ; Turn OFF timer1 00184 if ( PICMaster ) 0851 00185 MOVF DUMMY_PB, W ; 00186 else 00187 MOVF PORTB, W ; 00188 endif 079B 00189 ADDWF CCPR2L, F ; Update Compare register pair latch 1803 00190 BTFSC STATUS, C ; 0A9C 00191 INCF CCPR2H, F ; 00192 if ( PICMaster ) 08D3 00193 MOVF DUMMY_PD, F ; 00194 else 00195 MOVF PORTD, W ; 00196 endif 079C 00197 ADDWF CCPR2H, F ; 3008 00198 MOVLW 0x08 ; On match CCP2 = H level 009D 00199 MOVWF CCP2CON ; 3005 00200 MOVLW 0x05 ; Capture on every rising edge 0097 00201 MOVWF CCP1CON ; 1410 00202 BSF T1CON, TMR1ON ; Turn ON timer1 00203 ; 00204 ; 00205 ; 2860 00206 lzz goto lzz ; Loop waiting for interrupts (for use 00207 ; with PICMASTER) 00208 ; 00209 ; Here is where you do things depending on the type of RESET (Not a 00210 ; Power-On Reset). 1E03 00211 OTHER_RESET BTFSS STATUS,NOT_TO ; WDT Time-out? 280B 00212 WDT_TIMEOUT GOTO ERROR1 ; YES, This is error condition 00213 if ( Debug_PU ) 282F 00214 goto START ; MCLR reset, Goto START 00215 else 00216 GOTO MCLR_RESET ; MCLR reset, Goto MCLR_RESET 00217 endif 00218 ; 00219 if (Debug ) 0000 00220 END_START NOP ; END lable for debug 00221 endif 00222 ; 00223 ; 00224 org PMEM_END ; End of Program Memory 280B 00225 GOTO ERROR1 ; If you get here your program was lost 00226 00227 end : XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX : XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX XXXXX----------- ---------------: ---------------- ---------------- ---------------- ---------------X All other memory blocks unused. Program Memory Program Memory Errors : Warnings : Messages : Words Used: Words Free: 0 0 reported, 0 reported, DS00594B-page 22 102 3994 0 suppressed 13 suppressed 1997 Microchip Technology Inc. AN594 Please check the Microchip BBS for the latest version of the source code. Microchip’s Worldwide Web Address: www.microchip.com; Bulletin Board Support: MCHIPBBS using CompuServe® (CompuServe membership not required). APPENDIX F: nolist ;****************************************************************************** ; ; This is the custom Header File for the real time clock application note ; PROGRAM:CLOCK.H ; Revision:7-19-94 ; ;****************************************************************************** ; This is used for the ASSEMBLER to recalculate certain frequency ; dependant variables. The value of Dev_Freq must be changed to ; reflect the frequency that the device actually operates at. ; Dev_Freq EQU D’4000000’; Device Frequency is 4 MHz DB_HI_BYTE EQU (HIGH ((( Dev_Freq / 4 ) * 1 / D’1000’ ) / 3 ) ) + 1 LCD_INIT_DELAY EQU (HIGH ((( Dev_Freq / 4 ) * D’46’ / D’10000’ ) / 3 ) ) + 1 INNER_CNTR EQU 40 ; RAM Location OUTER_CNTR EQU 41 ; RAM Location ; T1OSO EQU 0 ; The RC0 / T1OSO / T1CKI ; RESET_V EQU 0x0000 ; Address of RESET Vector ISR_V EQU 0x0004 ; Address of Interrupt Vector PMEM_END EQU 0x07FF ; Last address in Program Memory TABLE_ADDR EQU 0x0400 ; Address where to start Tables ; COUNTER EQU 0x021 ; CCP2_INT_CNT EQU 0x33 ; ; ; DUMMY_PD:DUMMY_PB contain the value to be loaded into the CCP2 compare registers ; (CCPR2H:CCPR2L) ; DUMMY_PA EQU 0x50 DUMMY_PB EQU 0x51 DUMMY_PC EQU 0x52 DUMMY_PD EQU 0x53 DUMMY_PE EQU 0x54 ; ; ; CAPT_NEW_H:CAPT_NEW_L stores the NEW captured value and the result of the ; subtraction between this capture and the previous. ; CAPT_NEW_H:CAPT_NEW_L = CAPT_NEW_H:CAPT_NEW_L - CAPT_OLD_H:CAPT_OLD_L ; ; After all computations the new capture value is moved to the CAPT_OLD_H:CAPT_OLD_L ; in preperation for the next capture value. ; CAPT_NEW_H EQU 0x040 ; CAPT_NEW_L EQU 0x041 ; CAPT_OLD_H EQU 0x042 ; CAPT_OLD_L EQU 0x043 ; ; list 1997 Microchip Technology Inc. DS00594B-page 23 Note the following details of the code protection feature on PICmicro® MCUs. • • • • • • The PICmicro family meets the specifications contained in the Microchip Data Sheet. Microchip believes that its family of PICmicro microcontrollers is one of the most secure products of its kind on the market today, when used in the intended manner and under normal conditions. There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the PICmicro microcontroller in a manner outside the operating specifications contained in the data sheet. The person doing so may be engaged in theft of intellectual property. Microchip is willing to work with the customer who is concerned about the integrity of their code. Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as “unbreakable”. Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our product. If you have any further questions about this matter, please contact the local sales office nearest to you. Information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. No representation or warranty is given and no liability is assumed by Microchip Technology Incorporated with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise. Use of Microchip’s products as critical components in life support systems is not authorized except with express written approval by Microchip. No licenses are conveyed, implicitly or otherwise, under any intellectual property rights. Trademarks The Microchip name and logo, the Microchip logo, FilterLab, KEELOQ, microID, MPLAB, PIC, PICmicro, PICMASTER, PICSTART, PRO MATE, SEEVAL and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. dsPIC, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, microPort, Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM, MXDEV, PICC, PICDEM, PICDEM.net, rfPIC, Select Mode and Total Endurance are trademarks of Microchip Technology Incorporated in the U.S.A. Serialized Quick Turn Programming (SQTP) is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. © 2002, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper. 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