Switch between Fast and Slow Mode of i2c

[Spaark]

Is it possible to switch from the Slow-Mode to the Fast-Mode of i2c in the Programmcode? And how if it is possible?

I now use #use i2c(master,sda=PIN_C4, scl=PIN_C3, SLOW) and want to switch to #use i2c(master,sda=PIN_C4, scl=PIN_C3, FAST) when i press a key.

Thanks.
Spaark
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This message was ported from CCS's old forum
Original Post ID: 14077

[PCM programmer]

:=Is it possible to switch from the Slow-Mode to the Fast-Mode of i2c in the Programmcode? And how if it is possible?
:=
:=I now use #use i2c(master,sda=PIN_C4, scl=PIN_C3, SLOW) and want to switch to #use i2c(master,sda=PIN_C4, scl=PIN_C3, FAST) when i press a key.
---------------------------------------------------
The easiest way is to use hardware i2c mode, and then change
the baudrate by writing to the SSPADD register.

Here is a sample program. If your crystal frequency is
different from 8 MHz, then change the #define statement
for Fosc so that it's set to your frequency.

<PRE>
#define Fosc 8000000 // I'm using a 8 MHz crystal
<BR>
#include "c:\Program Files\Picc\Devices\16F877.H"
#fuses HS, NOWDT, NOPROTECT, BROWNOUT, NOLVP, PUT
#use delay(clock = Fosc)
#use rs232(baud = 9600, xmit=PIN_C6, rcv = PIN_C7, ERRORS)
<BR>
// Tell the compiler to use hardware i2c.
#use i2c(Master, SDA=PIN_C4, SCL=PIN_C3, FORCE_HW, slow)
<BR>
// Calculate the i2c baudrate values, to program
// into the SSPADD register.
#define SLOW ((Fosc / (4 * 100000)) -1) // 100 KHz i2c clock
#define FAST ((Fosc / (4 * 400000)) -1) // 400 KHz i2c clock
<BR>
#byte SSPADD = 0x93 // Address of i2c baudrate register
<BR>
//=====================================
void main()
{
char c;
<BR>
delay_us(1);
<BR>
while(1)
{
i2c_write(0x55);
<BR>
if(kbhit())
{
c = getc() & 0x5F;
<BR>
if(c == 'F') // If the F key is pressed, use Fast speed.
SSPADD = FAST;
<BR>
if(c == 'S') // If the S key is pressed, use Slow speed.
SSPADD = SLOW;
}
<BR>
}
<BR>
}
</PRE>
___________________________
This message was ported from CCS's old forum
Original Post ID: 14091