Raspberry Pi Zero 3 W and Pi 4 Model A on the Way?
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Two new Raspberry Pi boards have quietly turned up in Raspberry Pi’s Linux kernel tree, and neither of them is kind of what I’d have guessed. Device tree recordsdata for a Raspberry Pi Zero 3 W and a Raspberry Pi 4 Model A have landed (Phoronix spotted it first), and while there’s no official announcement simply but, system tree recordsdata have a tendency to offer away a shocking quantity for those who can decipher them and I gave it my finest shot.
Raspberry Pi Zero 3 W: A Pi 4 Shrunk Down?
The Raspberry Pi Zero 2 W launched nearly precisely 5 years in the past (tomorrow, in reality), so a successor has been a loooooong time coming. If you need a refresher on the place issues stood again then, my Raspberry Pi Zero 2 W vs Zero W benchmarks piece covers the bounce from the unique fairly properly.
The headline from the Zero 3 W device tree is the SoC. It’s the Broadcom BCM2711, the identical quad-core Cortex-A72 chip that powers the Raspberry Pi 4, changing the Zero 2 W’s quad-core 1GHz Cortex-A53 RP3A0. If you need an thought of the kind of hole we’re speaking about, it’s value taking a look at how those two compare on sbc.compare. That’s a giant step up in per-core efficiency, and if they will get something near Pi 4 clocks in that tiny footprint, it’ll be a hell of lots of compute for a Zero. I do marvel how toasty it’s going to get although, because the BCM2711 isn’t precisely recognized for operating cool, and there’s not lots of board for the warmth to unfold into. The system tree doesn’t inform us something about clock speeds, so we’ll have to attend and see whether or not it’s been dialled again.
Beyond the SoC, right here’s what else stood out to me:
- eMMC on a Zero? The storage controller is configured with an 8-bit bus width and a remark describing it as driving “the eMMC/SD card”, which solely actually is smart for eMMC. I’d like to see it, however I’m not anticipating it to make the ultimate board, because it’d push the worth up on a spread that lives and dies by its price ticket. My cash is on this being a leftover or an choice stored open throughout growth, and microSD being what we get.
- An SPI flash bootloader. The GPIO names embody SPI flash strains, which suggests the Zero 3 W will get the identical EEPROM-based bootloader because the Pi 4 (the Zero 2 W by no means had one). That ought to carry the Pi 4’s boot choices together with it, and the power to update the bootloader within the ordinary approach.
- A single HDMI output, with the second HDMI controller completely disabled. No shock there given the shape issue.
- An influence button outlined on GPIO 46 and mapped to KEY_POWER, so we could also be getting a bodily button (or no less than a header for one) very like the Pi 5.
- Wi-Fi and Bluetooth wired up in the identical approach as the remainder of the BCM2711 household, with a single ACT LED for standing.
- The ordinary 40-pin GPIO structure (GPIO 0-27 with the ID EEPROM pins), so your present HATs ought to be nice.
There are a few extra speculative bits too. The PCIe controller is enabled and there are strains named PCIE_PWR_EN and PCIE_DET_WAKE, and the digicam aspect pulls in a 4-lane CSI configuration somewhat than the 2-lane one the Pi 4 Model B makes use of. It’s value noting that each system timber share lots of copy-and-paste DNA (the Zero 3 W even has a duplicated “PWR_GPIO” line title), so I wouldn’t learn an excessive amount of into both of these till we see an precise board. I’d like to see PCIe uncovered on a Zero, however I’m not holding my breath.
Raspberry Pi 4 Model A: The Return of the A
The second shock is a Raspberry Pi 4 Model A. We haven’t had a Model A for the reason that Raspberry Pi 3 Model A+ again in 2018, and the method has all the time been the identical: take the Model B, strip out the bits most individuals can stay with out (RJ45, some USB ports and many others), and knock a piece off the worth. The Pi 4 Model A seems to comply with that recipe fairly intently, although the worth remark could not fairly maintain. Let’s see!
- No Ethernet. The Ethernet controller isn’t enabled anyplace, and the GPIO strains that drive the Ethernet PHY on the Model B have been repurposed. Very a lot consistent with earlier Model A boards.
- A single HDMI output somewhat than the Model B’s twin micro HDMI.
- No 3.5mm audio/composite jack. The analogue audio pins are empty and the composite video encoder is disabled, so audio can be over HDMI (or USB/I2S for those who’re that approach inclined).
- microSD solely, with the identical 1.8V signalling assist because the Model B for the quicker UHS card modes.
- External antenna assist. This is the one I discover most attention-grabbing. There are two antenna management strains (ANT_CTRL1 and ANT_CTRL2) and overlay parameters named
ant1,ant2andnoant, which is precisely how the Compute Module 4 switches between its onboard antenna and an exterior U.FL connector. If that carries over to the ultimate board, it’d be a stunning addition for anybody sticking a Pi in a metallic enclosure. - PWR and ACT LEDs, the identical SPI flash bootloader setup because the Model B, and the identical energy button definition because the Zero 3 W.
The system tree doesn’t inform us something about USB. On the Model B, the USB 3 ports made use of the PCIe bus, and the PCIe controller is enabled right here too, so USB 3 is feasible, however the 3 Model A+ solely had a single USB-A port and I’d most likely count on the identical right here.
How Do They Compare?
Here’s a fast side-by-side of what the system timber inform us, with the Pi 4 Model B thrown in for good measure. Anything marked with an asterisk is my interpretation of the system tree somewhat than one thing it states outright.
| Raspberry Pi Zero 3 W | Raspberry Pi 4 Model A | Raspberry Pi 4 Model B | |
|---|---|---|---|
| SoC | Broadcom BCM2711 | Broadcom BCM2711 | Broadcom BCM2711 |
| CPU | Quad-core Cortex-A72 | Quad-core Cortex-A72 | Quad-core Cortex-A72 |
| HDMI | 1x | 1x | 2x micro HDMI |
| Ethernet | No | No | Gigabit |
| Wi-Fi/Bluetooth | Yes | Yes, with antenna switching* | Yes |
| Storage | microSD (until..) | microSD | microSD |
| Analogue Audio/Composite | No | No | Yes (3.5mm) |
| SPI Flash Bootloader | Yes* | Yes* | Yes |
| Power Button | Yes* | Yes* | No |
| LEDs | ACT | PWR, ACT | PWR, ACT |
What We Don’t Know (Yet)
Quite rather a lot, I’m afraid. Device timber don’t describe RAM, so there’s no phrase on reminiscence configurations, and there’s nothing on pricing, clock speeds, connector sorts or a launch date both.
Pricing is the massive one for me. Memory prices haven’t precisely been type these days (I coated the final spherical of will increase alongside the 1GB Raspberry Pi 5 launch), and a lower-cost Pi 4 variant makes lots of sense in that context. The BCM2711 is a mature chip at this level, it’s properly supported in software program, and a cut-down board offers individuals who don’t want a Pi 5 one thing cheaper to succeed in for. The Zero 3 W is a more durable one to name although, because the Zero vary has all the time lived and died by its worth, and I can’t think about the BCM2711 being as low cost to construct round because the RP3A0.
Thoughts
On the entire, I like what I’m seeing right here. The Zero 3 W seems just like the improve lots of people have been asking for for the reason that Zero 2 W landed, and the 4 Model A appears like a wise approach of compacting extra life out of the Pi 4 platform at a time when parts aren’t getting any cheaper. The exterior antenna assist on the 4 Model A is a very nice contact if it makes it to the ultimate board.
Saying that, every part above comes from system tree recordsdata somewhat than an official spec sheet, so mileage could differ when the actual factor turns up. Kernel assist touchdown forward of launch is normally a great signal that it’s not far off, and you may guess I’ll be throwing each the Zero 3 W and the 4 Model A onto sbc.compare as quickly as I can get one in my palms.
Which of the 2 are you extra enthusiastic about? Do let me know within the feedback!
Sources
bcm2711-rpi-zero-3-w.dts
bcm2711-rpi-4-a.dts
Related posts: Raspberry Pi Zero 2 W vs Zero W Benchmarks – Pi Zero Showdown – 1GB Raspberry Pi 5 Launched Alongside Price Increases
