Example for a TC77?

[Birdasaur]

Does anyone out there have a bitbang or SPI_READ() example for a TC77? I've tried the CCS spi_read() calls, but they clock 8 bits, whereas the TC77 temperature register is a 13 bit register. Needless to say a simple read isn't helping me. I've also tried to do a simple bit bang, but its not working. In fact, I can't seem to get the TC77 to even respond using the bit bang. I've posted this question in another thread but it is not getting viewed. I thought maybe it deserved its own thread.

here's some code that DOES NOT WORK
//to try to bit bang the 13 bits
output_low(PIN_B1); //select the TC77
for(i=13; i>0; i--)
{
delay_us(10);
output_high(PIN_B2);
delay_us(10);
if (input(PIN_B3))
bit_set(data,i);
delay_us(10);
output_low(PIN_B2);
delay_us(10);
}
output_high(PIN_B1); //deselect the TC77


This code also fails

//To use the spi_read() function

output_low(PIN_B1); //select the TC77

temp1 = spi_read(0x00); //Read the 8 MSB of the data
temp2 = spi_read(0x00);

output_high(PIN_B1); //deselect the TC77

For the SPI_READ() code I've tried all manner of combinations of reads and writes and all return goofy results. I must be missing something simple, could somebody out there just point me back in the right direction?

[Birdasaur]

Here's the code that works like a dream. Turns out I had a couple jumpers interfering with my bitbang lines. (duh )

Also I had the clock order wrong, gotta lower the clock, than raise the clock BEFORE the data bit is clocked out.

I don't know how much of each delay is needed.

while(1)
{
delay_ms(1000);
data = 0;
F = 0;

output_low(PIN_B1); //select the TC77
for(i=13; i>0; i--)
{
output_high(PIN_B2); //clock
delay_us(10);
output_low(PIN_B2);
delay_us(10);
if (input(PIN_B3))
bit_set(data,i);
}
output_high(PIN_B1); //deselect the TC77

data >>= 6; //to get rid of the fraction of a degree

F = (unsigned int16) (1.8 * data) +32;
printf("\r\nThe temperature is: %lu C/%lu F \r\n",data,F);
}

Good luck to everyone, I hope this helps someone.

[wedilo]

Hi Birdasaur,
fine code snippet. Thank you...

BUT, in your first post you ask for some code and in your second post you give the answer yourself? Amazing...

73 Sven

[Birdasaur]

I try to contribute to the forum whenever I can. I've asked for a lot of help in the past and I want to be the "helper" too.

Also, noone answered me so I figured it was a mystery.

It was easier than I thought too.

Good luck everyone.

[wedilo]

Hello Birdasaur,
that's a great attitude.

Thank you and all the best
73 Sven

[>>TechDesign]

this one works too! (on a 16f877)
i took these non-standard pins, cause i need RC3 & RC4 for i?c routines..