atsamd51 atsame5x: change to allow specifying the ADC Bus number

[sago35]

For PB08 and PB09, and PA08 and PA09, it was not possible to select which ADC instance to use until now. Since the two ADC instances can be sampled at the same time, we want to be able to select which ADC instance to use.

https://ww1.microchip.com/downloads/en/DeviceDoc/SAM_D5x_E5x_Family_Data_Sheet_DS60001507G.pdf The SAM D5x/E5x has two ADC instances, ADC0 and ADC1. The two inputs can be sampled simultaneously, as each ADC includes sample and hold circuits.

	ADC0	ADC1
PB03	15
PC00		10
PC01		11
PC02		4
PC03		5
PA02	0
PA03	1
PB04		6
PB05		7
PD00		14
PD01		15
PB06		8
PB07		9
PB08	2	0
PB09	3	1
PA04	4
PA05	5
PA06	6
PA07	7
PA08	8	2
PA09	9	3
PA10	10
PA11	11
PC30		12
PC31		13
PB00	12
PB01	13
PB02	14

I tried to change the source code, but there may be a better way. Also, as I was making changes in src/examples/adc, I ended up with incompatible changes in environments other than atsamx5x. Would it be better to make sure that all environments except atsamx5x are not incompatible?

[sago35]

This is not directly related to this PR, but I noticed that the following sources can be unified. I'll discuss it in another PR / Issue.

• machine_atsamd51.go
• machine_atsame5x.go

[sago35]

This is not directly related to this PR, but I noticed that the following sources can be unified. I'll discuss it in another PR / Issue.

* machine_atsamd51.go

* machine_atsame5x.go

Fixed with #1845

[deadprogram]

I think there is probably a different way you can solve this @sago35 that does not require breaking the current API.

For example, your function getADCBus() could lookup which bus matches that pin. In the case that you really need to set which bus to use, then perhaps adding the bus number to https://github.com/tinygo-org/tinygo/blob/dev/src/machine/adc.go#L8

What do you think?

[sago35]

The original version of getADCBus() was implemented in such a way that if there were two candidates, it would return one of them. When a new getADCBus() decides which bus to use, there are two rules to follow.

If there is only one bus that the Pin can use, it will return that bus. If there are two busses available for the Pin, the bus is determined from the information stored in the ADC-struct.

Hmm, I can't think of a good way to do this.

[sago35]

The dev branch is in progress, so I rebased it.