Microchip’s PolarFire SoC household of chips, which mix a quad-core Linux-compatible 64-bit RISC-V CPU cluster and a fifth “monitor core” with a strong FPGA cloth right into a high-flexibility machine, have been gaining reputation — however what do you do should you do not want FPGA {hardware}?
In keeping with Microchip, you purchase a PIC64GX as a substitute — and it desires to show that with the Curiosity Package, a growth board mimicking the structure of the PolarFire SoC Discovery Package however with a PIC64GX1000 at its coronary heart. You may discover the identical SiFive U54 RISC-V cores and E51 monitor core, the identical 1GB of LPDDR4, and lots of the identical growth choices together with a mikroBUS header, however with out the PolarFire FPGA performance.
Will the Curiosity Package tempt builders to Microchip’s PIC64GX vary? Let’s go hands-on and discover out.
{Hardware}
- CPU: 4× SiFive U54 RV64GC at 600MHz (3.125 CoreMarks/MHz, 1.714 DMIPS/MHz), 1× E51 RV64IMAC at 600MHz
- GPU: None
- RAM: 1GB LPDDR4
- Storage: 32GB microSD card (included)
- Networking: 1× gigabit Ethernet
- Serial: 3× UART (through 1× USB Kind-C connector)
- Growth: mikroBUS header, MIPI RX, 14-pin “Consumer IO” header
- Extras: 2× push-button switches, 4× DIP switches, 8× user-addressable LEDs, HDMI output
- Programmer: On-board FlashPro 5, no exterior {hardware} required
- Energy: 5V through USB Kind-C or DC barrel jack
- Dimensions: 104×84mm (round 4.1×3.6″)
- Pack Contents: PolarFire SoC Curiosity Package board, stand-off pillars (pre-mounted), 32GB microSD card (pre-installed), USB Kind-C cable
- Value: $150
Curious certainly: the Curiosity Package appears to be like remarkably just like the Discovery Package, with a couple of vital variations. (📷: Gareth Halfacree)
At first look, it is simple to mistake the Curiosity Package for the Discovery Package and vice-versa. Each are constructed to a compact structure measuring roughly 4.1×3.6″, embody a USB Kind-C connector and mikroBUS socket to the left, a microSD card slot beneath, a MIPI RX connector suitable with Digicam Serial Interface (CSI) picture sensors, an Ethernet socket, and a choice of LEDs and switches.
The variations begin within the tough heart: the board’s foremost chip footprint now contains a machine smaller than the PolarFire SoC of the Discovery Package, a PIC64GX1000 microprocessor. It is successfully what you are left with should you take the “PolarFire” out of the “PolarFire SoC”: a system-on-chip that includes 4 SiFive U54 64-bit RISC-V cores operating at as much as 600MHz, and a fifth E51 core accountable for operating the Hart Software program Companies (HSS) that hold every thing ticking over.
As soon as you’ve got noticed that the chip’s modified, different variations make themselves identified. Subsequent to the MIPI RX connector is an HDMI port, one thing the Discovery Package lacks; there are fewer DIP and push-button switches, although the identical variety of user-addressable LEDs, and what’s labelled as a seven-segment show connector on the Discovery Package is now the “Consumer IO Connector” with 14 pins, two of which hook up with 3V3 and energy rails respectively.
Not like the Discovery Package, the Curiosity Package features a 32GB microSD card pre-loaded with Ubuntu Linux. (📷: Gareth Halfacree)
The Curiosity Package, then, is a quad-core single-board pc, however one which lacks a few of what you may count on from one, particularly one able to operating — and arriving with a 32GB microSD card pre-loaded with — Canonical’s Ubuntu Linux. There are not any USB ports, for starters, which means no straightforward technique to join a keyboard for interactive use. The 40-pin Raspberry Pi-compatible general-purpose enter/output (GPIO) header of the Discovery Package is completely absent on the Curiosity Package, too.
First boot
One main benefit of the Curiosity Package is that it arrives ready-to-run out-of-the-box. Simply join the board to a desktop or laptop computer utilizing the bundled USB Kind-C cable — for which you may have to provide your personal Kind-C to Kind-A adapter, in case your machine would not have Kind-C ports — and it will start besides. The one software program you want is FTDI serial port drivers, directions for putting in and configuring that Microchip supplies in its quick digital quick-start information.
Microchip features a 31-page quick-start information — 11 pages of which is burned getting UART connectivity working in Home windows. (📷: Microchip)
For many who have been postpone the Discovery Package by the effort of making use of for a Libero SoC license, modifying the license, and appropriately putting in and operating the licensing daemon, it is an actual breath of recent air: you will be up and operating inside two minutes. The bundled 32GB microSD card comes with a pre-installed copy of Canonical’s Ubuntu Server 24.04 LTS Linux distribution, and boots straight to a login immediate.
Right here, too, issues are far easier than the Discovery Package. The place the PolarFire SoC-powered Discovery Package’s “minimal Linux picture” is minimal certainly, missing even a DHCP consumer for simple community connectivity, the picture equipped with the Curiosity Package is fully-featured: community, time synchronization, and extra all work out-of-the-box on first boot with no configuration required, and there is the apt package deal supervisor with a big selection of software program awaiting your directions for extra.
Utilizing Ubuntu on the Curiosity Package is equivalent to utilizing it on every other machine, with a few caveats. The primary is that the processor cores in PIC64GX chip are RISC-V structure, which means that you may’t set up software program that is been compiled for x86 or Arm cores — and never all software program will recompile for RISC-V with out tweaking. That is not an excessive amount of of an issue, although: Canonical’s RISC-V repositories include a broad array of open-source software program, and you will nearly actually discover what you want in there with out having to supply third-party packages.
After a surprisingly gradual minute-long boot course of, you may be greeted by a well-known and fully-featured Ubuntu Server atmosphere. (📷: Gareth Halfacree)
The opposite caveat is that you may’t run a desktop — at the very least, not but. Now, which will appear apparent sufficient on a tool with simply 1GB of RAM — however there are light-weight desktops that’ll fortunately run in 1 / 4 of that. The PIC64GX, although, lacks a graphics processor; the HDMI port, by default, does nothing aside from present a plain blue backdrop.
Microchip’s documentation explains that the HDMI port is primarily there on your personal use, with the corporate saying it is potential to make use of the output for “easy overlays” or as a dwell view of a video feed from a picture sensor linked to the MIPI RX port. We’re instructed, nonetheless, {that a} driver that can enable Ubuntu to make use of the HDMI port as a video output is within the works.
Documentation
As is, sadly, a recurring theme for Microchip’s growth boards, the documentation is by far the weakest a part of the providing. The 31-page quick-start information outlines the board’s main elements, presents directions for getting the serial interface working in Home windows and Linux however not macOS, connecting to the UART terminal, putting in packages through apt, connecting and transferring recordsdata by means of SSH, operating a easy Python net server, and, for some cause, putting in and taking part in a text-mode Area Invaders clone.
GPIO, Dr. Falken? A wierd recreation. The one successful transfer is to not play. How a couple of good recreation of Area Invaders as a substitute? (📷: Microchip)
What it doesn’t cowl is utilizing the HDMI connector, whether or not for “easy overlays” or anything. It additionally would not point out use the “Consumer IO” connector, or the DIP switches, or the push-button switches, or the LEDs. It would not let you know use the MIPI RX port for a picture sensor. Nor does it supply any clues on make use of that mikroBUS connector, designed for simply including exterior {hardware} utilizing solder-free Click on modules.
Microchip does have a second doc, the PIC64GX1000 Curiosity Package Consumer Information. This, although, is much more sparse than the quick-start information: at simply 18 pages, it goes into temporary element about varied technical options like voltage measurement factors and the on-board oscillators however lacks any element that will be of use to a developer.
Lastly, Microchip presents a choice of GitHub repositories — together with one with pattern packages for the PIC64GX, the pic64gx-linux-examples repository. Sadly, even these fail to supply any clues as to the way you may use the assorted options of the Curiosity Package: there are two examples for Distant Process Name (RPC) messaging between Asynchronous Multiprocessing (AMP) situations, a function that permits you to cut up the quad-core chip in half and deal with it as two separate gadgets operating separate software program, one for System Tree overlays, and one for utilizing the Raspberry Pi Sense HAT with the chip — a potentially-useful instance rendered ineffective, because the Curiosity Package lacks the 40-pin header you’d want to truly hook up with a Sense HAT.
Not one of the temporary instance packages embody GPIO, HDMI, mikroBUS, or MIPI RX utilization, leaving you adrift. (📷: Microchip)
Different repositories include uBoot sources, a Zephyr real-time working system (RTOS) port and a handful of code examples, and every thing it is advisable construct your personal Linux photos for the board utilizing your selection of Yocto or Buildroot. Helpful, undeniably, however not lots of assist to anybody who simply desires to toggle an IO pin or flash an LED.
Microchip, to its credit score, has acknowledged this paucity of documentation, and is working to resolve this: the corporate guarantees a brand new quick-start information, which is able to cowl utilizing the DIP switches, the mikroBUS header, MIPI RX, HDMI, and extra, in larger element — and no fewer than 4 new utility notes on utilizing UART, SPI, I2C, and CAN buses, plus one other on utilizing the HDMI port as soon as work on the driving force is full. Preview copies of the primary few of those utility notes had been supplied as a part of the overview; all require that the consumer builds a recent Linux picture utilizing a Yocto board help package deal, and cannot be adopted utilizing the Ubuntu picture equipped nor any downloadable from Canonical.
Efficiency
Having 4 64-bit cores at your disposal might offer you concepts of operating computationally-intensive workloads on the machine, however expectations needs to be tempered: the SiFive U54 cores on the board run at simply 600MHz — slower than the identical cores on the PolarFire SoC Discovery Package, the place they run at 667MHz attributable to being higher-binned components — and are displaying their age somewhat now, failing to maintain up with the efficiency of extra fashionable RISC-V core designs and even previous-generation cores from Arm.
Efficiency is somewhat decrease than the PolarFire SoC Icicle Package on the identical workload — lots decrease than a Raspberry Pi 4. (📷: Gareth Halfacree)
In actual world phrases, you may count on to see a single-threaded efficiency a good bit above that of the Raspberry Pi Zero and its 32-bit ARM11 core — our single-threaded file compression benchmark has the Curiosity Package’s PIC64GX finishing the take a look at round 25 % sooner than the Raspberry Pi Zero. With all 4 cores operating, although, that hole widens: operating 4 compression threads the Curiosity Package completes the take a look at 73 % sooner, a performance-boosting trick the single-core Raspberry Pi Zero cannot comply with.
Transfer to a extra fashionable Raspberry Pi board, although, and the story modifications. For a similar workload, the PIC64GX is 5 instances slower than the previous-generation quad-core Raspberry Pi 4 for each single- and multi-threaded compression — and you could find related gaps for all different workloads, from cryptographic operations to floating-point math. Swap to the Raspberry Pi 5, and the hole turns into an order-of-magnitude distinction for a lot of workloads.
If it is somewhat unfair to check a comparatively early-generation RISC-V core to a well-established Arm core, there are different comparisons to be drawn. The PIC64GX runs at a ten % clockspeed deficit in comparison with the PolarFire SoC, so there is no shock in seeing a ten % real-world efficiency hole between the 2 — and whereas the PIC64GX manages to outperform the Nezha D1, the primary commercially-available Linux-capable RISC-V growth board launched 4 years in the past, it’s simply overwhelmed by StarFive’s VisionFive and newer VisionFive 2.
The unusually excessive idle energy draw, nearly 5 instances as a lot as a Raspberry Pi Zero, factors to a possible drawback. (📷: Gareth Halfacree)
All this could possibly be simply defined by a concentrate on energy effectivity; the PIC household, in spite of everything, has historically been nothing however microcontrollers designed for low-power embedded operation. The Curiosity Package, although, attracts a stunning quantity of energy: at idle it attracts 2.8W, round 4 instances as a lot because the Raspberry Pi Zero and drawing stage with the Raspberry Pi 4, rising to three.3W should you join an Ethernet cable; at full load this goes as much as 3.6W, greater than twice that of the Raspberry Pi Zero however comfortably under the 6.9W of the extra highly effective Raspberry Pi 4.
A have a look at the board beneath a thermal digital camera reveals that the distinction in energy draw if you join an Ethernet cable just isn’t an phantasm: the Vitesse Ethernet PHY chip simply reaches temperatures above 60°C (140°F) — but the “gigabit” Ethernet port it drives can also be performance-constrained and reached a most sustained throughput of simply 603Mb/s in our testing.
Conclusion
Anybody who’s learn our protection of the Microchip PolarFire SoC Icicle Package, Video Package, or Discovery Package will see that little has modified in how the corporate might enhance the expertise for its prospects: documentation, documentation, documentation. Taking a web page out of the already-limited quick-start information to put in Area Invaders whereas ignoring the options that probably attracted the client to the board — GPIO connectivity, that MIPI RX port, the mikroBUS connector, even the HDMI video output — is, certainly, a curious resolution, and the shortage of pattern code to cowl the hole is saddening to see. That Microchip acknowledges this and is actively working to unravel the issue, although, is heartening, and it could be fascinating to revisit the board in six months or so to see simply the place that effort has led.
The PIC64GX is an fascinating chip, however with out satisfactory documentation it is arduous to discover its true potential. (📷: Gareth Halfacree)
It is disappointing to see the PIC64GX chip itself embody PCI Specific connectivity for high-speed peripherals, however to not have it made obtainable to the consumer on the event board itself. The rising variety of equipment for the Raspberry Pi 5, which features a single PCIe Gen. 2 lane on a flat versatile circuit (FFC) connector on the fringe of the board, reveals how a lot demand there’s for this connectivity — and breaking it out would imply customers might flip the Curiosity Package right into a extra general-purpose single-board pc by including their very own USB 3.0 controller. This, too, is a criticism Microchip is trying to handle, telling us to count on PCIe connectivity “in future kits for upcoming PIC64GX derivatives,” together with chip variants that includes on-board graphics processing engines.
The largest adverse for the Curiosity Package, although, is its pricing. At $150, it is not at all costly — nevertheless it is available in at $18 greater than the Discovery Package, a tool that features the very same CPU cores, solely sooner, the identical RAM, the identical microSD slot, and lots of the identical growth capabilities — shedding, admittedly, the HDMI connector and bundled microSD card however gaining a 40-pin Raspberry Pi-compatible GPIO header and extra on-board switches. It additionally contains the PolarFire FPGA cloth, which you would be free to disregard should you’re concentrating on RISC-V and Linux growth — saving your self the $18 and gaining the potential to department out into FPGA tasks sooner or later with out spending a penny extra. Microchip, for its half, tells us that at the very least among the value differential is defined by variations in manufacturing volumes — and that it’s shifting to extend manufacturing of the Curiosity Package, which it hopes “will yield general value reductions sooner or later.”
In the event you’re prepared to roll your personal Linux, you would be a lot better off selecting up the extra highly effective but cheaper Discovery Package than the Curiosity Package. (📷: Gareth Halfacree)
A giant benefit to the Curiosity Package is the simplicity with which you’ll be up and operating in a RISC-V Linux atmosphere. The place the Discovery Package requires you to flash a particular gateware on the FPGA cloth and both run the extraordinarily cut-down Linux construct from Microchip or create your personal, the Curiosity Package is supported by Canonical’s official RISC-V Ubuntu builds: Ubuntu 24.04 LTS and the short-term-support Ubuntu 25.04 are already obtainable to obtain, and future releases ought to comply with. These, nonetheless, is not going to be supported within the firm’s utility notes, which means anybody trying to make use of options like GPIO and the mikroBUS connector might want to roll their very own working system picture anyway.
The Curiosity Package is now obtainable to order from Microchip direct at $150; the board may also be ordered from Avnet.
