Bare breakout boards for new AVR DX-series future Ex-series, and the ATmega4809/4808

The AVR Dx-series (ex: AVR128DA64, AVR128DB48 etc) is the latest and greatest line of AVR microcontrollers, and these bring the AVR product line onto a whole new level, with higher clock speeds (up to 24 MHz (rated - i have some that will do twice that), all the way from 1.8V to 5.5V), with a 12-bit ADC, 10-bit DAC, 2 Type A timers (on 48/64-pin parts), in a package with 28, 32, 48, or 64 pins. These breakout boards are meant for use with the AVR DA, AVR DB, AVR DD, older ATmega 0-series, and future AVR-EA and AVR EB-series parts. (Kudos to Microchip for largely maintaining pin compatibility!)

The 32-pin versions are currently being revised to support the full range of full sized modern AVRs announced, the DA32, DB32, DD32, EA32. and EB32. It is possible that the DB and DD 32 will be skipped as we have another product planned for them and the MVIO greatly complicates matters.

However, the AVR DA/DB64 and AVR DA/DB48 boards ARE now available! These feature a bunch of new features: * Three sets of regulator pads: a A "main" regulator to supply Vdd, and optionally, either a fixed voltage 1117-series regulator, or a MAX25301A for MVIO. The MAX25301A allows 9 different voltage to be selected, and is connected to the least useful pins I could find on the chip. Voltage can be selected between 1V2, 1V5, 1V8, 2V5, 3V0, 3V1, 3V3, 4V0, 5V0, with minimum dropout at a full 1A current of only around as little as 48mV. The output voltage can be changed on the fly and starts up disabled. [See the library documentation for more info] https://github.com/SpenceKonde/DxCore/tree/master/megaavr/libraries/AzduinoMAX38903 for more info)

This is sold as a BARE BOARD - the assembled board is pictured as a reference for assembly and to give an indication of what they will look like once you put parts on them.

Available as assembled board too

The purpose of these boards is to provide a no-nonsense breakout board that effectively gives you something you could either program over UPDI or treat like an Arduino Pro Mini with a serial bootloader - only with a much fancier chip. The pending version of these boards will be compatible with all of the current and announced non-tiny AVR product lines that have parts with appropriate pincounts (DA and DB only thus far for the 64-pin, DA, DB, and EA for 48 pin, and DA, DB, DD, RA, and EB, (though the Ex-series isn't yet available, it's coming). These break out every pin on these exciting new parts to easily accessible 0.1" pin header, and provide pads for a SOT-223 regulator (like a 1117-series - we recommend the LDL1117 for their extra-low dropout and fairly low quiescent current and compatibility with cheap abundant ceramic capacitors), and have a 3-pin header for UPDI programming and a 6-pin FTDI-style serial header (with auto-reset support) Even better, with my DxCore, the new AVR Dx-series and future Ex-series can be programmed in Arduino too!. They are very similar to the megaAVR 0-series (as supported by MegaCoreX, but have a ton more memory, and many of the peripherals have had small new features added. The Ex-series will take a step back in memory sizes, while adding a super fancy new ADC starting with the EA-series, and introducing two new types of timer with the likely-motor-control oriented EB.

Board Power subsystem (Rev. B and later)

Because the Rev. B supports the AVR DB-series parts, which have two power domains (unless disabled), the power supply circuitry is a lot more complicated. The DB is the only 64 or 48 pin part with MVIO thus far. For other microcontrollers, a considerable number of pads are likely to remain unpopulated, particularly on the 64-pin ones,

On the DB64

Here we pulled out more of the stops A Second regulator may be installed for the MVIO rail. This may be either fixed voltage (1.8, 2.5, 3.3. 5.0 - can be higher or lower than Vdd) or a selectable voltage. * In the selectable voltage option, a MAX38093 regulator is used (1.2*, 1.5*, 1.8, 2.5, 3.0, 3.1 3.3, 4.0 or 5.0V. These are controlled by pins PE6, PG6, and PG7 - those were the least useful pin I could find on the parts - PE6 is the enable line which must not be used for other purposes while using the regulator. The other two pins are only checked at the moment the chip is enabled, and after that they may be used for other purposes. The setMAX38903Voltage() function proviced by the included AzduinoMAX38093.h allows this configuration) * In the selectable configuration, the regulator must be running at very close to the same voltage as the chip - that is why these are only sold with bypassed or 5v regulators. A 5.3v power source (like many USB phone chargers) could run the chip at 5V through a fixed regulator, and input voltage could also supply the selectable output regulator with just enough headroom to get 5V out of it as well! If a 3.3v fixed voltage regulator is used for MVIO, You may install an ESP01M module. See the schematic for the full connections provided. We belive, but have not yet tested this functionality, and as such cannot yet provide guarantees (and that's why we don't sell ESP-01M's as an optional addon) yet, that this could be used with the AT firmware to grant interntet access to an AVR128DB64, or with custom firmware handling the web interface, and the AVR handling he low level and 5v-needing parts. If MVIO is not beng used, especially if it is disabled in the fuses too, you must bridge the MVIO_disable jumper below the pads for the MVIO regulator, which will tie VDDIO2 to Vdd. As long as MVIO is enabled in the fuses, you may leave MVIO disable unconnected, not install either regulator, and instead get power to MVIO through other means - for example, you might use one of the on-chip OPAMPs, and connect it's output pin to a VDDIO2 pin, and set it up as a voltage follower from the DAC (gets you maybe 20 mA max though). * The DB64 supports a crystal. loading caps for one are installed on PA0 and PA1, and the pads to connect those pins to anything other that the crystal are not bridged prior to shipment (we don't know if you're buying it witthout a crystal because you're planning to use your own, or because you're going to use the internal oscillator!). Bridge them if not using a crystal or external clock.

On the DA64

The DA64 has only one power domain, and as such, many of these features are less useful. Only the first regulator should ever be installed (and as always may be bypassed). Disable MVIO should always be bridged. The following parts should always be omitted: R5, C10, C11, C13, C14, C16, C17, C18, U4, U3, R1, Y2. * The DA may not take a crystal, hence unless an external oscillator is used, Y3 should be omitted as well along with C15. * If an external oscillator is used, connect the OSCPWR bridge on the back, install an appropriate decoupling cap on C15 per manufacturer datasheet, * Otherwise, bridge the unconnected side of the PA1 jumper, and the PA0 jumper to enable use of those pins for other things. We do this in house for assembled boards. The ESP8266 can be installed on a 3.3v board, and should work there. Again, untested. These bridges should remain unchanged on the DA in 99% of use cases: VINROUTE, VCC2MV, and VSER should be left on "VCC", or cut to disconnect serial, but should not be connected to Vin. As on my other boards, cutting VREG will disconect the regulator output from Vcc (maybe saving power?)

On all parts

• RBP - Bridging this bypasses the 470 ohm series resistor on the UPDI line.
• TXS and RXS select whether the FTDI header connects to PA0/1 or PA4/5, since the former may be needed for the clock.
• VUP - Cutting this disconnects the Vdd pin of the UPDI header from Vdd of the board
• RST_EN - cut to disable autoreset.
• CTS can be connected to either UPDI, Gnd, or the XDIR pin of USART0.
• Use the XDS jumper to thoose which XDIR pin you want.
• If using a watch crystal for the RTC, install it in Y1.
• If not using a watch crystal for the RTC, bridge F0 and F1 pads to connect those lines to the holes at the edge of the board

The reason for the solder-bridge jumpers on all the crystal pins is that crystals are very sensitive to the parasitic capacitance of long traces and will not work if the traces all the way to a hole along the edge are connnected. To save power, the modern AVR's don't drive the crystal as hard, and well, this is the cost of that.

The back of the board has a handy reference table listing the ports, and the number of the USART and CCL LUT number that makes it's "home" on that port, the number of ADC pins on that port, and the number of TCA or TCD PWM pins. TCB channels aren't listed, because you should use TCBs are a last resort for PWM, not a first resort. Even Microchip admits they're bad PWM timers. That's not what they were designed for.

AVR Dx/Ex 48

The 48 pin parts didn't have as much space on the board to go crazy, So I didn't go as crazy, and the result is more coherent.

AVR DB48

• You must supply VDDIO2 externally or from the DAC + an OPAMP. There is only one regulator, and it supplies Vdd.
• Cutting the right-hand bridge from the MVIO jumper will disconnect VDD from VDDIO2, bridge the other side to connect it to the VDDIO2 pins at the bottom.

AVR EA48 and DB48 only

These parts support a crystal which can be installed as a 3225, 5032, or radial ("garbage can shaped") crystal. Install not more than one.. The pads for enabling PA0, PA1 are IOENA and IOENB. Bridge those if not using a crystal (this board noes NOT support an external clock). Cut the existing bridge and complete the other one to move the FTDI port to the alt pins if using a crystal. * Omit C9, C10, and Y1 if not using a high frequency crystal.

AVR DA48, ATmega4809, or AVR EA48

• Bridge IOENA, IOENB (unless an EA48 using a crystal).
• Leave the *SEL bridges in their default positions (unless an EA48 using a crystal, or you need to move the USART0 to PA4/5/6/7 for some other reason.
• You may omit C11 (this is an extra 1 uF decoupling cap on VDDIO2 for the DB, as recommended by microchip, in parallel with C1, a 0.1uF decoupling cap)

For all parts

• If not using a watch crystal, bridge IOENC, IOEND to permit use of those I/O pins. The TXSEL, RXSEL jumpers on the back control whether the FTDI header connects to PA0/1 or PA4/5.
• CTS Can be routed to either UPDI (default), Ground, or the XDIR pin using the provided solder bridge jumpers. The DIO jumper likewise connects the DTR pin directly to an I/O pin (recommended to cut RSTEN) - specifically to the XCK pin of USART0. The XDSEL and XCSEL solder bridge pairs select primary or alternate.
• Omit Y2, C7 and C8 if not using a watch crystal.
• Remember to do Serial.swap(1) (in Arduino w/DxCore or MegaCoreX) or set the PORTMUX appropriately to switch to the alt pins if you have used the *SEL bridges.

~You can see the full bill of materials on the google doc at the Documentation link, which also describes all aspects of these boards (in both bare and assembled as we sell them) in excruciating detail.~ This needs to be updated for the Rev. B, as do the product photos - we have shifted to ENIG surface treatment, blue solder mask to improve readability and made a number of significant enhancements to the board design and layout.

Stencil gerbers

Got a laser cutter handy, or buying and making a large number of boards? (note - if you ever need more then I have in inventory, I can get more fairly quickly) You probably want a STENCIL. Hereare the stencil gerbers ready to be made by OSH or yourself, if you have a laser cutter. Azduino Stencil Page