PIC18f4550 does not support MDD format i was told that it would be fixed in the next versions.. you can use SPI format for that purpose... its easy.. you just need to need to read and write FAT file system..........
MMC <--SPI-->PIC18f4550 <---USART--->PC
I want to read/write in the MMC using SPI protocol then the data to be written is from PC via UART.. is it possible??
the data trying to write is wav file.. is it possible?
A single transmission error can possibly corrupt the wave data. That's why people prefer special encoding and transmission protocols with consistency checks for binary data.
However, the said problem is far beyond this thread's topic. I generally think, people shouldn't encourage the original poster to continue the thread like an off-topic chat or personal blog. Strictly spoken, it's against the forum rules.
void shift_right()
{
char c;
if(P1 == 0x04)
{
P2 = 0xA0;
for(c=0; c<3; c++)
{
delay_ms(1000);
P2 = P2 >> 1;
}
}hi have something to ask... hehe
I did a shift right routine as a laboratory exercise of one of my subjects but I think there's another way of writing better than this code...
}PHP:void shift_right() { char c; if(P1 == 0x04) { P2 = 0xA0; for(c=0; c<3; c++) { delay_ms(1000); P2 = P2 >> 1; } }
plz help me i m beginner in pic and MPLab.......in the pic 16f877a i use timer0.....and than i use T0CON (timer0 control). the MPLab complier give the :
Error [192] F:\PIC16F877A\MPLab\test_2.c; 10.1 undefined identifier "T0CON"
plz plz help me.!
5.0 TIMER0 MODULE
The Timer0 module timer/counter has the following
features:
• 8-bit timer/counter
• Readable and writable
• 8-bit software programmable prescaler
• Internal or external clock select
• Interrupt on overflow from FFh to 00h
• Edge select for external clock
Figure 5-1 is a block diagram of the Timer0 module and
the prescaler shared with the WDT.
Additional information on the Timer0 module is
available in the PICmicro® Mid-Range MCU Family
Reference Manual (DS33023).
Timer mode is selected by clearing bit T0CS
(OPTION_REG<5>). In Timer mode, the Timer0
module will increment every instruction cycle (without
prescaler). If the TMR0 register is written, the increment
is inhibited for the following two instruction cycles.
The user can work around this by writing an adjusted
value to the TMR0 register.
Counter mode is selected by setting bit T0CS
(OPTION_REG<5>). In Counter mode, Timer0 will
increment either on every rising or falling edge of pin
RA4/T0CKI. The incrementing edge is determined by
the Timer0 Source Edge Select bit, T0SE
(OPTION_REG<4>). Clearing bit T0SE selects the rising
edge. Restrictions on the external clock input are
discussed in detail in Section 5.2 “Using Timer0 with
an External Clock”.
The prescaler is mutually exclusively shared between
the Timer0 module and the Watchdog Timer. The
prescaler is not readable or writable. Section 5.3
“Prescaler” details the operation of the prescaler.
5.1 Timer0 Interrupt
The TMR0 interrupt is generated when the TMR0
register overflows from FFh to 00h. This overflow sets
bit TMR0IF (INTCON<2>). The interrupt can be
masked by clearing bit TMR0IE (INTCON<5>). Bit
TMR0IF must be cleared in software by the Timer0
module Interrupt Service Routine before re-enabling
this interrupt. The TMR0 interrupt cannot awaken the
processor from Sleep since the timer is shut-off during
Sleep.
C:\Program Files\HI-TECH Software\PICC\9.81\include
Code C - [expand]
Hi Romel,
What is the actual purpose of the code snippet?
Is the one second delay within the for loop for display purposes? Is P2 being displayed on LEDs, etc?
plz help me i m beginner in pic and MPLab.......in the pic 16f877a i use timer0.....and than i use T0CON (timer0 control). the MPLab complier give the :
Error [192] F:\PIC16F877A\MPLab\test_2.c; 10.1 undefined identifier "T0CON"
plz plz help me.!
#include<pic.h>
__CONFIG(0x3F38); //for Internal oscillator
char count;
void interrupt timer0()
{
if(T0IF == 1)
{
T0IF = 0;
count++;
if(count == 15)
{
RA2 ^= 1; //toggle LED
count = 0;
}
}
T0IE = 1; //Disables the TMR0 interrupt
}
void main(void)
{
TMR0 = 0;
OPTION_REG = 0b0111; // set prescaler to timer 0 and 1:256 prescaler..
T0CS = 0; // timer 0 Internal clock source
T0IE = 1; // enable timer 0 interrrupt
GIE =1; // Enable global interrupt
TRISA2 = 0; //set bit 1 of portB as output.
while(1);
}yes. It's just being displayed on 8 LEDs connected to P2.
Code C - [expand]
Code C - [expand]
The technique of using shadow registers, prevents unforeseen changes in the state of a volatile register, e.g. PORT2, from corrupting the calculation or routine's outcome.
void shift_right()
{
[COLOR="#FF0000"]char c; // unsigned char c; A good policy[/COLOR]
if(P1 == 0x04)
{
P2 = 0xA0;
for(c=0; c<3; c++)
{
delay_ms(1000);
P2 = P2 >> 1;
}
}
}
Code C - [expand]
void main()
{
//working code
unsigned char i;
P2=0x00;
while(1)
{
delay_ms(1000);
P2 = 0x00; // to clear the previous value of port
i=i>>1;
if(i==0)
i=0x80;
P2=P2|i;
}
}void main()
{
//problematic code. hehe
signed char i;
P2=0x00;
while(1)
{
delay_ms(1000);
P2 = 0x00;
i=i>>1;
if(i==0)
i=0x80;
P2=P2|i;
}
}A.5.5 The result of a right shift of a negative-valued signed integral type (6.3.7)
The right shift operator sign extends signed values. Thus an object with the signed int value 0x0124 shifted right one bit will yield the value 0x0092 and the value 0x8024 shifted right one bit will yield the value 0xC012. Right shifts of unsigned integral values always clear the most significant bit of the result. Left shifts (<< operator), signed or unsigned, always clear the least significant bit of the result.
you have always a reference as a prof.. hehe
by the way did you read all this things up before?
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