Having trouble with SERIN command and MAX6675

[Bruce]

You want to read each bit on the falling edge of the clock so use mode 2. And you only need to shift MXtemp >> 3. Not 5.

[emerson]

You want to read each bit on the falling edge of the clock so use mode 2. And you only need to shift MXtemp >> 3. Not 5.

I changed both but there's still no response? On the datasheet it says the MAX6675 serial clock frequency is 4.3MHz, and I'm running my pic at 4MHz, will this effect data communication?

[Bruce]

If you have an O-scope check the data out pin. That will at least let you know if it's responding.

[emerson]

If you have an O-scope check the data out pin. That will at least let you know if it's responding.

the O-scope test checked out alright

[emerson]

I just disabled the comparators in the chip but it still won't. I even replaced the thermocouple and the MAX76675 but i get the same response. I have no idea what could be wrong with this. Any ideas?

[Bruce]

Have you tried sending the raw value received 'without modifying it' to your LCD while heating or cooling the part?

Something like: lcdout $fe, $c0, BIN16 MXtemp

Does it change when heated?

Edit: Since you're using the internal osc on this one, place Define OSCCAL_1K 1 in the top section. Not sure it that will fix it, but it will for sure affect timing.

[emerson]

Have you tried sending the raw value received 'without modifying it' to your LCD while heating or cooling the part?

Something like: lcdout $fe, $c0, BIN16 MXtemp

Does it change when heated?

Edit: Since you're using the internal osc on this one, place Define OSCCAL_1K 1 in the top section. Not sure it that will fix it, but it will for sure affect timing.

I just tried it and there is no change

[Bruce]

What's the 16-bit value shown?