MAX 6675 (thermocouple) very slow with C3
karelk
Posts: 4
Hi All,
I try to use the MAX6675 thermocouple-to-SPI chip (from Adafruit) with the C3 propeller. Actually, I have two 6675's connected, with shared Gnd, Vcc, CLK and data-out (MISO), and individual chip select (SPI channels 6 and 7 of the C3).
Although the timing (e.g. the clock frequency is 17 kHz) are easily within specs of the MAX 6675 chip, I can only measure it about 5 times per second.
If I try to read it faster (same clock freq, but more measurements per second) the chip does not seem to update its data.
I'm using the source code (all in spin) from the AD-converter example for the C3, and modified it to read from the other SPI channels.
Anyone an idea wether I should look for a solution in the electronics or in the software?
Should I simply measure it faster, or minimize noise, or reduce transient-effects of the chip select and clock pulses?
Many thanks in advance,
Greetings,
Karel
I try to use the MAX6675 thermocouple-to-SPI chip (from Adafruit) with the C3 propeller. Actually, I have two 6675's connected, with shared Gnd, Vcc, CLK and data-out (MISO), and individual chip select (SPI channels 6 and 7 of the C3).
Although the timing (e.g. the clock frequency is 17 kHz) are easily within specs of the MAX 6675 chip, I can only measure it about 5 times per second.
If I try to read it faster (same clock freq, but more measurements per second) the chip does not seem to update its data.
I'm using the source code (all in spin) from the AD-converter example for the C3, and modified it to read from the other SPI channels.
Anyone an idea wether I should look for a solution in the electronics or in the software?
Should I simply measure it faster, or minimize noise, or reduce transient-effects of the chip select and clock pulses?
Many thanks in advance,
Greetings,
Karel
Comments
Thanks for clearing that up!
I completely overlooked that info, and misread a comment somewhere else.
Greetings,
Karel