I2C for Heltec Mesh Node T114 #4745
Conversation
todd-herbert
force-pushed
the
t114-i2c
branch
from
acbb66c to
b6adeae
Compare
Think about to use this mapping:
Heltec T114 pin header
|
That's definitely a reasonable suggestion. My first hope was to match the qwIIC mapping Heltec used on their other Vision Master boards, but this wasn't possible because 3.3V and GND are reversed. After the disappointment with the qwIIC mapping, I didn't think to check for any alternative layouts. If the pin-out in your photos is another common layout for I2C devices, then definitely it's worth swapping the SCL and SDA assignment, so at least it can be convenient in some cases. |
todd-herbert
force-pushed
the
t114-i2c
branch
from
f12e67d to
097e505
Compare
Enabled at compile-time if WIRE_INFERFACES_COUNT defined as 2
SDA: P0.13 SCL: P0.16 Uses bus 1, leaving bus 0 routed to the unpopulated footprint for the RTC (general future-proofing)
SDA=P0.16, SCL=P0.13
todd-herbert
force-pushed
the
t114-i2c
branch
from
097e505 to
7690055
Compare
| #ifndef WIRE_INTERFACES_COUNT | ||
| // Officially an NRF52 macro | ||
| // Repurposed cross-platform to identify devices using Wire1 | ||
| #if defined(I2C_SDA1) || defined(PIN_WIRE_SDA) |
There was a problem hiding this comment.
@todd-herbert shouldn't this be PIN_WIRE_SDA1 here?
Based on meshtastic#4745, PIN_WIRE1_SDA is the 'second' wire interface. This pach amends the check to determine whether a device has two wire interfaces should use PIN_WIRE1_SDA, rather than PIN_WIRE_SDA.
Based on #4745, PIN_WIRE1_SDA is the 'second' wire interface. This pach amends the check to determine whether a device has two wire interfaces should use PIN_WIRE1_SDA, rather than PIN_WIRE_SDA.
|
@fifieldt Ah thank you for spotting that! |
|
Wondering how were you flashing T114 as there is no model available at web flasher? |
Resolves #4605
Adds an I2C bus, assigned to P0.13 (SDA) and P0.16 (SCL), which are available on the header pins.
This is implemented using a second I2C bus.
Bus 0 retains its original assignment from Heltec: routed to the footprint for an RTC which is not populated on the current hardware version.
Another option would be to simply reassign the pins for the currently unused I2C bus 0.
Is there reason to consider this instead?