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SomuSundram
Joined: 04 Aug 2013
Posts: 1
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| HCTL-2017 HighByte LowByte |
 Posted: Sun Aug 04, 2013 7:30 am |
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Hello all,
I'm trying to read HCTL-2017 Quad Decoder/Counter chip. I got it working in BS2. However, I can't get it working in CCS C compiler, which does not have HighByte-LowByte functions? And i'm kinda puzzled with the make() functions as well. Below is my code -
| Code: |
#include <16F877A.h>
#device adc=10
#FUSES NOWDT //No Watch Dog Timer
#FUSES HS //High speed Osc (> 4mhz for PCM/PCH)
#FUSES PUT //Power Up Timer
#FUSES NOPROTECT //Code not protected from reading
#FUSES NODEBUG //No Debug mode for ICD
#FUSES BROWNOUT //Reset when brownout detected
#FUSES NOLVP //No low voltage prgming,
#FUSES NOCPD //No EE protection
#FUSES NOWRT //Program memory not write protected
#use delay(clock=20000000)
#use rs232(baud=19200,xmit=PIN_C6,rcv=PIN_C7,bits=8)
//#use fast_io(A)
//#use fast_io(B)
//#use fast_io(C)
//#use fast_io(D)
//#use fast_io(E)
void Encoder(void);
int16 encoderLastL,encoderThisL;
int16 encoL,encoH;
void main()
{
setup_comparator(NC_NC_NC_NC);
setup_vref(0);
set_tris_a(0b01100001); // 0 = Analog
set_tris_b(0b11111111); // HCTL1 Inputs
set_tris_c(0b10000000);
set_tris_d(0b11111111);
set_tris_e(0b00000000);
setup_adc_ports(AN0);
setup_adc(ADC_CLOCK_INTERNAL);
setup_ccp2(CCP_PWM);
setup_timer_2(T2_DIV_BY_4, 255, 1); // 4.88 kHz PWM
set_pwm1_duty(0); // initialize PWM off
output_low (PIN_C0); //Motor DIR.
output_high(PIN_A1); //Reset HCTL-1
output_high(PIN_A4); //Reset HCTL-2
delay_ms(100);
while(1)
{
output_high(pin_E0); //OE HCTL-1
output_high(pin_E1); //SEL HCTL-1 (L-Bytes,H-Bytes)
encoH = input_b();
output_low(pin_E1); //SEL HCTL-1
encoL = input_b();
output_low(pin_E0); //OE HCTL-1
encoderThisL = make16(encoL,encoH);
encoderLastL = encoderThisL;
printf("EncoderLast: %Lu \n\r",encoderLastL);
//printf("\n\r");
//printf("EncoderThis: %d \n\r",encoderThisL);
}
}
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Can anyone help me?Or how to read the HighBytes & LowBytes straight from the pins?
Thanks! |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19506
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| Posted: Sun Aug 04, 2013 7:47 am |
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CCS can deal with high/low bytes, using standard C.
| Code: |
struct bytes {
int8 low;
int8 high;
};
union {
struct bytes b;
int16 word;
} val;
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Then val.b.low is the low byte, val.b.high is the high byte, and val.word is the 16bit word.
So val.b.high = input_b(); will read the high byte directly.
Make16 though also does it, and should work as you show.
If it doesn't work, you probably have something else wrong...
The obvious fault is basic. You are putting OE high. This disables the output. OE is an active low signal (read the data sheet.....). Similarly you have the byte select the wrong way round. '0' (low) gives the high byte. You are selecting high.....
Best Wishes |
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jeremiah
Joined: 20 Jul 2010
Posts: 1346
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| Posted: Sun Aug 04, 2013 8:32 am |
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| Quote: |
| Code: |
encoderThisL = make16(encoL,encoH);
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One possible issue with how you are using make16() is the order of your parameters. make16() takes high byte first. |
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