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RobS
Joined: 29 Jan 2005
Posts: 10
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| Port pin configuration question |
 Posted: Wed Jun 08, 2005 2:29 pm |
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I am using a PIC 18LF8720. CCS compiler PCWH ver 3.206. At the start of the program there are three port pins, J4, J6 and H4 that are set as output using the SET_TRIS_H( 0xba ) and SET_TRIS_J( 0xa0 ) commands. All three pins are pulled low with 10K resistors.
Following this H4 is set high using the output_high(PIN_H4) and J4 is pulsed high using the output_high(PIN_J4), delay_ms(1500) and then output_low(PIN_J4). Nothing is done with J6.
If an out of spec condition occurs a function is called which then pulses J6 using output_high(PIN_J6), delay_ms(250) and then output_low(PIN_J6) and sets H4 low using output_low(PIN_H4).
Very occasionally there is some strange behavior where J6 is high as measured with a DVM. The out of spec condition did not occur and I believe the software did not do this.
At the start of the program is it ok to just set J6 as an output using the SET_TRIS_ ( ) or do you have to write to it also?
Thanks |
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Ttelmah
Guest
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| Posted: Wed Jun 08, 2005 2:49 pm |
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You can set the pin as an output, but what voltage it presents will depend on what is in the output latch. Remember though that if you do not use the '#use fast_io' directive, the next time the bit is accessed, the setting will be overridden.
I am puzzled by the values you specify for the tris statements. As given, H4, for example, is set as an input. Remember a '1' is an input, and a '0' is an output. 0xba, gives:
10111010
With H0, H2 & H6 set as outputs, and the other bits as inputs.
Best Wishes |
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RobS
Joined: 29 Jan 2005
Posts: 10
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| Posted: Wed Jun 08, 2005 4:00 pm |
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Most pins in my application will not change configuration but one port is used as both input and output so I will not use '#use fast_io' directive.
Instead of H4 i ment H6 so it should be ok. thanks for catching this.
I have to update the software so I will set J6 low at the start of the program.
thanks for your input |
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treitmey
Joined: 23 Jan 2004
Posts: 1094
Location: Appleton,WI USA
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| Posted: Thu Jun 09, 2005 10:36 am |
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| Do you understand that is it posible to use it as both in and out with the fast_io directive. Right? |
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RobS
Joined: 29 Jan 2005
Posts: 10
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| Posted: Fri Jun 10, 2005 9:41 am |
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Yes I believe you can use it as both in and out with fast_io directive but will have to change the configuration with the Set_Tris before using it as the new configuration.
That is if set as an input use Set_Tris(0) and then output_high/low.
If set as an output use Set_Tris(1) and then input(PIN)
Right? |
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treitmey
Joined: 23 Jan 2004
Posts: 1094
Location: Appleton,WI USA
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| Posted: Mon Jun 13, 2005 8:12 am |
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More likely set_tris_b(0b00000001)//out,out,out,out,out,out,out,in
or set_tris_b(0xFF)//all in
But you can also overlay a struc on the tris register. Like below.
This won't compile,.. I commented out the unimportant stuff. See
how use 2 strucs[the same definition],.. 1 on the pins, 1 on the tris reg. Then I define the read rtc_tris_r() with the AD(address data bus) as inputs. You can change any bit or the whole thing at any time. The only thing is you use #fast_io on those ports.
| Code: |
///////////////////////////////////////////////////////////////////////////
// Name : ds12887.c //
// Author : Timothy Reitmeyer //
// Notice : Copyright (c) 2004 Sentinel Systems Corporation //
// : All Rights Reserved //
// Date : 05-05-2005 //
// Version: 1.00 //
///////////////////////////////////////////////////////////////////////////
//05/09/2005 07:25AM initial program with driver. This file is the Driver
/* time, date & alarm regs */
//#define CLK_SECS 0 //MSbit of secs is read only
//#define CLK_SECS_ALM 1 //MSbit of secs is read only
//#define CLK_MINS 2
//#define CLK_MINS_ALM 3
//#define CLK_HRS 4
//#define CLK_HRS_ALM 5
//#define CLK_DOW 6
//#define CLK_DOM 7
//#define CLK_MON 8
//#define CLK_YR 9
//#define REGA 10 //BIT 7 READ-ONLY all others r/w
//#define REGB 11 //READ/WRITE REGISTER
//#define REGC 12 //READ-ONLY REGISTER
//#define REGD 13 //READ-ONLY REGISTER
//#define nvram_min 14 //addresses 14-127 available for use as nv ram
//#define nvram_max 127
////Comment out the text if your not using it to save on ram
//const char dow_text[8][4] =
//{
// "---",// -0-
// "Mon",// -1-
// "Tue",// -2-
// "Wed",// -3-
// "Thr",// -4-
// "Fri",// -5-
// "Sat",// -6-
// "Sun" // -7-
//};
////Comment out the text if your not using it to save on ram
//const char month_text[13][4] =
//{
// "---",// -0-
// "Jan",// -1-
// "Feb",// -2-
// "Mar",// -3-
// "Apr",// -4-
// "May",// -5-
// "Jun",// -6-
// "Jul",// -7-
// "Aug",// -8-
// "Sep",// -9-
// "Oct",// -10-
// "Nov",// -11-
// "Dec"// -12-
//};
struct rtc_pin_def
{ //Motorola timing/bus (must have mot(pin1) tied to Vdd.
//Read is data from ds12887 to micro. Write is data from micro to ds12887
BOOLEAN cs_bar; // C0 CS must be kept in the active state during DS and AS for mot
BOOLEAN as; // C1 falling edge of AS latches. The next rising AS clears address regardless of whether CS is asserted.
BOOLEAN rw_bar; // C2 Read,Write_bar
BOOLEAN ds; // C3 During read cycles, DS signifies the time that the DS12887 is to drive the bidirectional bus. In write cycles the trailing edge of DS causes the DS12887 to latch the written data.
BOOLEAN reset_bar; // C4 Reset active low
BOOLEAN irq_bar; // C5 IRQ input active low,read reg C to return irq_bar=1
BOOLEAN rclr_bar; // C6 Unused ..rclr_bar
BOOLEAN swq; // C7 Square Wave out of ds12887
int8 ad; // PortD=Address and Data bus
};
//struct rtc_rega_struc
//{
// BOOLEAN RS0;//RS0-3 //1) Enable the interrupt with the PIE bit;
// BOOLEAN RS1; //2) Enable the SQW output pin with the SQWE bit;
// BOOLEAN RS2; //3) Enable both at the same time and the same rate; or
// BOOLEAN RS3; //4) Enable neither.
// BOOLEAN DV0;//DV0-2 A pattern of 010 to turn on RTC first time
// BOOLEAN DV1;//DV0-2 A pattern of 11X enables the oscillator but holds the countdown in reset.
// BOOLEAN DV2;
// BOOLEAN UIP;//UIP The update-in-progress status flag to be monitored
//} rega_var;
//struct rtc_regb_struc
//{
// BOOLEAN DSE; //1=Daylight Savings Enable
// BOOLEAN MIL; //1=24 hour military clock or 12 standard household clock
// BOOLEAN DM; //1=binary data while a 0 =BCD data.
// BOOLEAN SQWE;//1=a square-wave signal at the frequency set by bits RS3-RS0
// BOOLEAN UIE; //1=IRQ on update-ended.
// BOOLEAN AIE; //1=IRQ on alarm flag,when three time bytes equal the three alarm bytes.
// BOOLEAN PIE; //1=IRQ at a rate RS3-RS0.0=IRQ blocked,but the periodic flag (PF) bit is still set.
// BOOLEAN SET; //1=update transfer is inhibited and the program can initialize the time and calendar bytes without an update occurring,0=normal advancing,
//} regb_var;//0b00001100
//struct rtc_regc_struc
//{
// BOOLEAN bit0;
// BOOLEAN bit1;
// BOOLEAN bit2;
// BOOLEAN bit3;
// BOOLEAN UF;//bit is set after each update cycle.
// BOOLEAN AF;//1=current time has matched the alarm time.
// BOOLEAN PF;//periodic-interrupt flag. Read-only bit that is set to a 1 when an edge is detected
// BOOLEAN IRQF;
//} regc_var; //Read only
//struct rtc_regd_struc
//{
// BOOLEAN bit0;
// BOOLEAN bit1;
// BOOLEAN bit2;
// BOOLEAN bit3;
// BOOLEAN bit4;
// BOOLEAN bit5;
// BOOLEAN bit6;
// BOOLEAN VRT;//Valid RAM time. If zero the lithium battery is dead
//} regd_var;//Read only
struct rtc_pin_def rtc; //pins for the rtc
struct rtc_pin_def rtc_tris;//tris for the rtc
#byte rtc = 0xF82 //note: no semicolin 0x82=C0 on a 18F452
#byte rtc_tris = 0xF94 //tris location for port C pin 0
#define rtc_tris_r() rtc_tris=0;rtc_tris.ad=0xFF//read data is input
#define rtc_tris_w() rtc_tris=0;rtc_tris.ad=0//write data is output
////============Prototypes=================================//
//void init_rtc(void);
////void model_num(void);
//char read_rtc(char addr);
//void write_rtc(char addr,char data);
//void set_time(void);
////============Funtions===================================//
//void write_rtc(char addr,char data)
//{
// //C7=swq,6=rclr_bar,5=irq_bar,4=reset_bar,3=ds,2=rw_bar,1=as,0=cs_bar
// rtc_tris_w();
// rtc.cs_bar=0;//chip active
// rtc.ad=addr; //addr is on bus
// rtc.rw_bar=0;//write mode
// rtc.ds=0; //data strob idle
// rtc.as=1; //addr strob
// delay_cycles(1); // pause
// rtc.as=0; //latch address
// rtc.ds=1; //data strob idle
// rtc.ad=data; //data is on bus
// delay_cycles(1); // pause
// rtc.ds=0; //latch data
// rtc_tris_r(); //set the tris of C and D to ALL INPUTS
//}
////=======================================================//
//char read_rtc(char addr)
//{
// //C7=swq,6=rclr_bar,5=irq_bar,4=reset_bar,3=ds,2=rw_bar,1=as,0=cs_bar
// char data;
// rtc_tris=0b11100000;//set the tris of C for setting address
// rtc_tris.ad=0x00; //set the tris of D for setting address
// rtc =0b00011110;//set C for for setting address
// rtc.ad=addr; //put address on bus
// #asm nop #endasm //pause
// rtc.as=0; //latch
// delay_cycles(1); // pause
// rtc_tris.ad=0xFF; //set the tris of D for reading data
// rtc.ds=0; //release
// #asm nop #endasm //pause
// data=rtc.ad; //read the data from the bus
// rtc_tris_r(); //set the tris of B and D to ALL INPUTS
// return(data);
//}
////=======================================================//
//void init_rtc()
//{
// rtc_tris.reset_bar=0;//set the tris of C
// rtc.reset_bar=0; //reset
// delay_ms(200);// delay the required time for reset
// rtc.reset_bar=1; //release
// rtc_tris_r(); //set the tris of C & D to ALL INPUTS
// while(rega_var.UIP);//wait for update to finish
// regd_var=read_rtc(REGD);
// if(regd_var.VRT) fprintf(DEBUG,"Lithium battery OK\n\r");
// else fprintf(DEBUG,"Lithium battery dead\n\r");
//
// rega_var=0;
// // //RS3:0 0=None,1=256Hz,2=128Hz,3=8.192kHz,4=4.096kHz,5=2.048kHz,6=1.024kHz
// // //7=512Hz,8=256Hz,9=128Hz,A=64Hz,B=32Hz,C=16Hz,D=8Hz,E=4Hz,F=2Hz
// // //RS3:0=5 =2kHz sqr wave
// // rega_var.RS0=1;//RS0-3 //1) Enable the interrupt with the PIE bit;
// // rega_var.RS1=1; //2) Enable the SQW output pin with the SQWE bit;
// // rega_var.RS2=1; //3) Enable both at the same time and the same rate; or
// // rega_var.RS3=1; //4) Enable neither.
// // rega_var.DV0=0;//DV0-2 A pattern of 010 to turn on RTC first time
// // rega_var.DV1=1;//DV0-2 A pattern of 11X enables the oscillator but holds the countdown in reset.
// // rega_var.DV2=0;
// // rega_var.UIP=0;//UIP The update-in-progress status flag to be monitored
// // write_rtc(REGA,(int8)rega_var); //set reg A
// write_rtc(REGA,0b11110100); //set reg A
//
// // //write_rtc(REGB,0b00001000); //set reg B
// // //write_rtc(REGB,0b01000100); //(msb) SET,PIE,AIE,UIE,SQWE,DM,MIL,DSE (lsb)
// // regb_var.DSE=0; //1=Daylight Savings Enable
// // regb_var.MIL=0; //1=24 hour military clock or 12 standard household clock
// // regb_var.DM=1; //1=binary data while a 0 =BCD data.
// // regb_var.SQWE=1;//1=a square-wave signal at the frequency set by bits RS3-RS0
// // regb_var.UIE=0; //1=IRQ on update-ended.
// // regb_var.AIE=1; //1=IRQ on alarm flag,when three time bytes equal the three alarm bytes.
// // regb_var.PIE=0; //1=IRQ at a rate RS3-RS0.0=IRQ blocked,but the periodic flag (PF) bit is still set.
// // regb_var.SET=0; //1=update transfer is inhibited and the program can initialize the time and calendar bytes without an update occurring,0=normal advancing,
// // write_rtc(REGB,(int8)regb_var);
// write_rtc(REGB,0b11111100); //(msb) SET,PIE,AIE,UIE,SQWE,DM,MIL,DSE (lsb)
//}
//
////================set the time and date======================//
//void set_time()
///* Note: NO error checking is done on the user entries! */
//{
// char yr, mn, dt, dy, hr, min, sec;
// char input[10];
// regb_var=read_rtc(REGB);
// if(regb_var.DM=1) /* Binary data */
// {
//
// fprintf(DEBUG,"\nEnter the year (0-99): ");
// fgets(input,DEBUG);//scanf("%bd", &yr);
// yr=atoi(input);
// fprintf(DEBUG,"\n\rread %u\n\r",yr);
//
// fprintf(DEBUG,"Enter the month (1-12): ");
// fgets(input,DEBUG);// scanf("%bd", &mn);
// mn=atoi(input);
// fprintf(DEBUG,"\n\rread %u\n\r",mn);
//
//
// fprintf(DEBUG,"Enter the date (1-31): ");
// fgets(input,DEBUG);// scanf("%bd", &dt);
// dt=atoi(input);
// fprintf(DEBUG,"\n\rread %u\n\r",dt);
//
// fprintf(DEBUG,"Enter the day (1-7): ");
// fgets(input,DEBUG);// scanf("%bd", &dy);
// dy=atoi(input);
// fprintf(DEBUG,"\n\rread %u\n\r",dy);
//
// if(regb_var.MIL=1) /* if 24 hour mode */
// {
// fprintf(DEBUG,"Enter the hour (1-23): ");
// fgets(input,DEBUG);//scanf("%bd", &hr);
// hr=atoi(input);
// fprintf(DEBUG,"\n\rread %u\n\r",hr);
// }
// else
// {
// fprintf(DEBUG,"Enter the hour (1-11): ");
// fgets(input,DEBUG);//scanf("%bd", &hr);
// hr=atoi(input);
// fprintf(DEBUG,"\n\rread %u\n\r",hr);
//
// fprintf(DEBUG,"A)M or P)M (A/P) " );
// fgets(input,DEBUG);//scanf("%1bs", &min);
// if(input == 'P' || input == 'p')
// hr |= 0x80; /* add PM indicator */
// }
// fprintf(DEBUG,"Enter the minute (0-59): ");
// fgets(input,DEBUG);//scanf("%bd", &min);
// min=atoi(input);
// fprintf(DEBUG,"\n\rread %u\n\r",min);
// fprintf(DEBUG,"Enter the second (0-59): ");
// fgets(input,DEBUG);//scanf("%bd", &sec);
// sec=atoi(input);
// fprintf(DEBUG,"\n\rread %u\n\r",sec);
//
// }
// else /* BCD data mode */
// {
//// fprintf(DEBUG,"\nEnter the year (0-99): ");
//// scanf("%bx", &yr);
//// fprintf(DEBUG,"Enter the month (1-12): ");
//// scanf("%bx", &mn);
//// fprintf(DEBUG,"Enter the date (1-31): ");
//// scanf("%bx", &dt);
//// fprintf(DEBUG,"Enter the day (1-7): ");
//// scanf("%bx", &dy);
//// if(REGB & 2) /* if 24 hour mode */
//// {
//// fprintf(DEBUG,"Enter the hour (1-23: ");
//// scanf("%bx", &hr);
//// }
//// else
//// {
//// fprintf(DEBUG,"Enter the hour (1-11:) ");
//// scanf("%bx", &hr);
//// fprintf(DEBUG,"A)M or P)M (A/P) ");
//// scanf("%1bs", &min);
//// if(min == 'P' || min == 'p')
//// hr |= 0x80; /* add PM indicator */
//// }
//// fprintf(DEBUG,"\nEnter the minute (0-59): ");
//// scanf("%bx", &min);
//// fprintf(DEBUG,"Enter the second (0-59): ");
//// scanf("%bx", &sec);
// }
//
//
// regb_var.SET=1;// REGB |= 0x80; /* inhibit update while writing to clock */
// write_rtc(REGB,(int8)regb_var); //set reg B
//
// write_rtc(CLK_SECS,sec);// CLK_SECS = sec;
// write_rtc(CLK_MINS,min);// CLK_MINS = min;
// write_rtc(CLK_HRS,hr);// CLK_HRS = hr;
// write_rtc(CLK_DOW,dy);// CLK_DOW = dy;
// write_rtc(CLK_DOM,dt);// CLK_DOM = dt;
// write_rtc(CLK_MON,mn);// CLK_MON = mn;
// write_rtc(CLK_YR,yr);// CLK_YR = yr;
// //irq on alarm, alarm set to don't care in all 3 bytes..ie: irq on each second
// write_rtc(CLK_HRS_ALM,0xFF); // CLK_HRS_ALM= 0xFF;//ie:don't care
// write_rtc(CLK_MINS_ALM,0xFF);// CLK_MINS = 0xFF;//ie:don't care
// write_rtc(CLK_SECS_ALM,0xFF);// CLK_MINS = 0xFF;//ie:don't care
//
// regb_var.SET=0;// REGB &= 0x7f; /* allow update of buffered set of time & date registers */
// write_rtc(REGB,(int8)regb_var); //set reg B
//}
//=======================================================//
//void model_num(void) /* ------ determine the model number of the RTC ------ */
//{
// REGA |= 0x10; /* select bank 1 */
// XBYTE[0x40] ^= 0xff; /* try to write to compliment data */
// if( (XBYTE[0x40] ^ 0xff) != XBYTE[0x40] ) /* if bits cannot be written, it's
// bank 1 */
// {
// model = XBYTE[0x40];
// }
// else
// {
// XBYTE[0x40] ^= 0xff; /* restore original data */
// model = 0; /* default if device does not support model number */
// }
// REGA &= 0xef; /* select bank 0 */
// printf("\nModel: ");
// switch(model)
// {
// case 0x71: printf("DS1687"); break;
// case 0x72: printf("DS17287"); break;
// case 0x73: printf("DS1691/93"); break;
// case 0x74: printf("DS17487"); break;
// case 0x78: printf("DS17887"); break;
// default: printf("DS12887");
// }
//}
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