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10 years, 4 months ago.
Values for ELEC0 and ELEC1 - connecting different electrodes?
How would I sense capacitive touch on my own, off-board electrodes connected to two pins? I'm not sure what the values 9 and 10 for ELEC0 and ELEC1 in the example refer to.
Using PinNames doesn't seem to work - I tried PinNames TSI_ELEC0, TSI_ELEC1 (defined in PinNames.h for the KL25Z), but this breaks the example code.
Question relating to:
2 Answers
10 years, 4 months ago.
Hello Bjoern Hartmann,
yes, the TSI library uses TSI peripheral channels, not PinNames as you noticed. You can implement a proper mapping of PinName - TSI channel and send a pull request to TSI library.
Regards,
0xc0170
10 years, 4 months ago.
According to the schematic it is PTB16 and PTB17. http://mbed.org/platforms/KL25Z/#technical-reference
TSI_ELEC0 and TSI_ELEC1 are aliases for PTB16 and PTB17 - their values (in PinNames.h) are:
- PTB16 = 0x1040,
- PTB17 = 0x1044,
- TSI_ELEC0 = PTB16,
- TSI_ELEC1 = PTB17
Using these constants in the FRDM TSI code template does *not* work. Instead, the code needs "magic" values 9 and 10.
My question was where these magic values come from and how I'd find other values to connect sliders to other pins.
I may have found the answer on page 44 of the KL25 datasheet (http://cache.freescale.com/files/32bit/doc/data_sheet/KL25P80M48SF0.pdf) It lists the default pin function for PTB16 as "TSIO_CH9" and PTB17 as "TSIO_CH10"
So apparently the TSI library wants channel IDs instead of pin names.
Here's my summary of pin name to channel mapping:
- PTA0 - TSI0_CH1
- PTA1 - TSI0_CH2
- PTA2 - TSI0_CH3
- PTA3 - TSI0_CH4
- PTA4 - TSI0_CH5
- PTB0 - TSI0_CH0
- PTB1 - TSI0_CH6
- PTB2 - TSI0_CH7
- PTB3 - TSI0_CH8
- PTB16 - TSI0_CH9
- PTB17 - TSI0_CH10
- PTB18 - TSI0_CH11
- PTB19 - TSI0_CH12
- PTC0 - TSI0_CH13
- PTC1 - TSI0_CH14
- PTC2 - TSI0_CH15
Have you found a solution to use the different available channels?
posted by John Miller 16 Sep 2016