Hi all,
Having looked at Frank's Flexiboard design, it spurred me to moving forward on an idea for a general purpose motherboard for the new 3.5 / 3.6 Teensies.
Most of my projects are one offs, and creating a specific PCB for each is a pain, specially as I reuse favourite components for instance a rotary encoder + TFT or touch TFT for the UI...
The specialist bits usually have I2C or SPI interfaces or simple digital / analogue I/O. Most need +5 or +3.3V.
Having a quick look around at the marketplace for specialist modules, there seem to be a bunch of SPI/I2C modules for "Arduino" + Uno style shields + mikroBus modules.
The mikroBus standard has a nice bunch of pins for most things:
• SPI
• I2C
• 1 x Analog
• 1 x Digital (PWM)
• 1 x Interrupt
• 5V, 3.3V power & GND
My initial thoughts on a spec for such a board are:
I have something like this in mind as a layout:
What would you add, delete or counsel me to change in this?
Richard
Having looked at Frank's Flexiboard design, it spurred me to moving forward on an idea for a general purpose motherboard for the new 3.5 / 3.6 Teensies.
Most of my projects are one offs, and creating a specific PCB for each is a pain, specially as I reuse favourite components for instance a rotary encoder + TFT or touch TFT for the UI...
The specialist bits usually have I2C or SPI interfaces or simple digital / analogue I/O. Most need +5 or +3.3V.
Having a quick look around at the marketplace for specialist modules, there seem to be a bunch of SPI/I2C modules for "Arduino" + Uno style shields + mikroBus modules.
The mikroBus standard has a nice bunch of pins for most things:
• SPI
• I2C
• 1 x Analog
• 1 x Digital (PWM)
• 1 x Interrupt
• 5V, 3.3V power & GND
My initial thoughts on a spec for such a board are:
- 3 x mikroBus - each with separate CS, etc. Possibly separate SPIs, as the Teensy 3.5/6 have multiple SPIs available.
- 3 x 16 pin headers (underneath the mikroBus ports) and connected to the mBus pins, to use for IDC cable extenders.
- 1 x 14 pin touch TFT header (2.8"/3.5"). The MCUfriend type SPI interface seems to be quite common now. So, a TFT header on the back of the PCB, as in the Flexiboard design.
- 2 or 3 ordinary 2 x 4 pin SPI headers - maybe in parallel with the mikroBus headers.
- 5V -> 3.3V LDO regulator + power jack
- All fitting as close to possible into the Eagle (free) board size and the shadow of a 3.5" TFT. (2.8" is too small, as the mikroBus footprint is reasonably chunky).
I have something like this in mind as a layout:
What would you add, delete or counsel me to change in this?
Richard