Internal Temperature Sensor for LPC832

[aaronm]

In the example ADC code for the LPC824MAX evaluation board, the comments refer to an internal temperature sensor on ADC0, channel 1.  I don't see anything specific about it in the documentation for the LPC824, and a google search doesn't really turn up any answers.  Is there an official source for the internal temperature sensor?  And does this same sensor exist on the LPC832 chip?  I could use this to seed the random number generator, if I can confirm it exists and works as expected.  My first pass with the ADC0 conversion on channel 1 on the LPC832 returns 0s, which doesn't seem correct.

[xiangjun_rong · Accepted solution]

Hi,

I have checked all the UM of LPC8xx, none of them has on-chip temperature senor, so  you can not use the on-chip ADC to measure the junction temperature for LPC8xx.

I have checked the ADC code in SDK package for LPC84x, but it is a bug, it should have  been deleted.

#if !(defined(FSL_FEATURE_ADC_HAS_NO_INSEL) && FSL_FEATURE_ADC_HAS_NO_INSEL)
/* Use the temperature sensor input to channel 0. */
ADC_EnableTemperatureSensor(DEMO_ADC_BASE, true);
#endif /* FSL_FEATURE_ADC_HAS_NO_INSEL. */

For the LPC processor, if it has on-chip temperature senor, it should have the register.

The LPC8xx does not have the Input Select Register.

Hope it can help you

BR

XiangJun Rong