<story><title>A Raspberry Pi 5 is better than two Pi 4S</title><url>https://hackaday.com/2023/09/28/a-raspberry-pi-5-is-better-than-two-pi-4s/</url></story><parent_chain><item><author>Wowfunhappy</author><text>I hate USB-C. What a mess.&lt;p&gt;What good is a universal port if it&amp;#x27;s not actually universal? I would actually prefer different shapes, because then you could be pretty confident that if everything fit it was going to work. Like how USB used to be.</text></item><item><author>Denvercoder9</author><text>You&amp;#x27;re both correct, but USB Power Delivery, like so many things USB, is a total mess with different revisions, and versions of those revisions, that each extend and deprecate parts of the previous revision. I&amp;#x27;m going to ignore the actual protocol used for negotiation here, but there have also been at least three different protocols.&lt;p&gt;The first revision, rev 1.0, had six fixed power profiles: 5V&amp;#x2F;2A, 12V&amp;#x2F;1.5A, 12V&amp;#x2F;3.0A, 12V&amp;#x2F;5.0A, 20V&amp;#x2F;3.0A and 20V&amp;#x2F;5.0A. These were deprecated by rev 2.0, version 1.2, which instead introduced power rules at four fixed voltages, supporting power supplies with different output powers. The maximum supported currents by the specification were 5V&amp;#x2F;3A, 9V&amp;#x2F;3A, 15V&amp;#x2F;3A and 20V&amp;#x2F;5A. These power rules were retroactively named the Standard Power Range (SPR) in rev 3.1. That revision also added the Extended Power Range (EPR), which raised all the current limits up to 5A, but only when used with electronically marked cables. EPR also added power rules at 28V, 36V and 48V, again requiring (differently) marked cables and up to 5A. So 5V&amp;#x2F;5A is a valid option, but only when used with a USB PD rev 3.1 compatible power supply and cable.&lt;p&gt;Orthogonally to the fixed power rules, rev 3.0 introduced the Programmable Power Supply, which allows a configurable voltage between 3.3V and 21V in steps of 20 mV. This was extended by rev 3.1 with voltages between 15V and 48V in steps of 100 mV, called the Adjustable Voltage Supply. As far as I&amp;#x27;m aware this is not commonly used, and most products advertising Power Delivery support use the predefined power rules.</text></item><item><author>coder543</author><text>No, Wikipedia is looking like it&amp;#x27;s out of date or wrong. It’s &lt;i&gt;not&lt;/i&gt; a definitive source, especially for highly technical topics like this.&lt;p&gt;Here is another industry source which has a table that also says 5V at 5A: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.graniteriverlabs.com&amp;#x2F;en-us&amp;#x2F;technical-blog&amp;#x2F;usb-power-delivery-specification-3-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.graniteriverlabs.com&amp;#x2F;en-us&amp;#x2F;technical-blog&amp;#x2F;usb-po...&lt;/a&gt;&lt;p&gt;In fact, using Wikipedia’s sources, I found the actual specs and here is another piece of supporting evidence for these other articles:&lt;p&gt;&amp;gt; The Fixed PDOs Maximum Current field Shall advertise at least 3A, but May advertise up to RoundUp (PDP&amp;#x2F;Voltage) to the nearest
10mA. Requires a 5A cable if over 3A is advertised.[0]&lt;p&gt;This is a footnote attached to 5V3A, indicating to me that chargers are allowed to offer more than 3A at 5V.&lt;p&gt;At a minimum, the spec seems to be ambiguously written, but I’ve only spent a few minutes skimming it. Multiple industry sources (previously linked) believe that 5V@5A is within the spec, even without using PPS.&lt;p&gt;[0]: “USB_PD_R3_1 V1.8 2023-04”</text></item><item><author>KennyBlanken</author><text>It&amp;#x27;s not hard to find at all.&lt;p&gt;&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;USB_hardware#USB_Power_Delivery&quot; rel=&quot;nofollow noreferrer&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;USB_hardware#USB_Power_Deliver...&lt;/a&gt;&lt;p&gt;5v3A is the limit of USB PD SPR.</text></item><item><author>coder543</author><text>I don’t agree. I found this straightforward statement:&lt;p&gt;&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.anandtech.com&amp;#x2F;show&amp;#x2F;16712&amp;#x2F;usbc-power-delivery-hits-240w-with-extended-power-range&quot; rel=&quot;nofollow noreferrer&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.anandtech.com&amp;#x2F;show&amp;#x2F;16712&amp;#x2F;usbc-power-delivery-hit...&lt;/a&gt;&lt;p&gt;&lt;pre&gt;&lt;code&gt;    &amp;gt; USB-PD R3.1 supports three charging models:
    &amp;gt; - Fixed voltage
    &amp;gt; - Programmable power supply (PPS), and
    &amp;gt; - Adjustable voltage supply (AVS).
    &amp;gt; In the fixed voltage scheme, the Standard Power Range (SPR) mode supports 3A and 5A at 5V, 9V, 15V, and 20V.
&lt;/code&gt;&lt;/pre&gt;
That’s about as clear as it can be, assuming AnandTech is correct.&lt;p&gt;Also keep in mind the existence of PPS as another data point. I have an Anker charger sitting in front of me that offers 3.3V-11V at 5A. 5V at 5A falls squarely in that range, as long as you have an e-marked cable that can support 5A. (I have no idea if the Pi 5 supports negotiating PPS, but it would increase compatibility with chargers if it does.)&lt;p&gt;I agree the Pi 5 should have included a buck converter or something, but I don’t think it’s correct to say they’re not standards compliant. It’s just not a common use of the standard.</text></item><item><author>p1mrx</author><text>&amp;gt; It also supports USB-C Power Delivery, so finding a power supply that’s capable of supplying all that juice to the Pi 5 is a lot easier&lt;p&gt;Isn&amp;#x27;t this mostly false? The Pi4 uses 15W at 5V3A.  The standard says, to exceed 15W you should increase the voltage, but Pi5 increased the amperage instead.  5V5A USB-PD supplies are almost unheard of.&lt;p&gt;I wonder how much a 9V3A -&amp;gt; 5V5A buck converter dongle would cost.</text></item></parent_chain><comment><author>Guvante</author><text>Is it really worse now than it was before?&lt;p&gt;Having a plug on say a laptop that can be a charger, a HID, a drive, a monitor, or all of the above with a docking station is vastly superior to the old day IMHO.&lt;p&gt;Unfortunately the cable to do that isn&amp;#x27;t cheap and is massively overkill for say a phone charger. Thus cable compatibility becomes a thing but looking at HDMI cable compatibility is always a thing.&lt;p&gt;I think the problem is what used to be complaints about niche connectors are complaints about USB-C and it feels different and more impactful even if it isn&amp;#x27;t necessarily.&lt;p&gt;After all I know back in the Mini-USB days you had manufacturers skipping the data pins to save some copper leading to frustration when you couldn&amp;#x27;t transfer files.</text></comment>
<story><title>A Raspberry Pi 5 is better than two Pi 4S</title><url>https://hackaday.com/2023/09/28/a-raspberry-pi-5-is-better-than-two-pi-4s/</url></story><parent_chain><item><author>Wowfunhappy</author><text>I hate USB-C. What a mess.&lt;p&gt;What good is a universal port if it&amp;#x27;s not actually universal? I would actually prefer different shapes, because then you could be pretty confident that if everything fit it was going to work. Like how USB used to be.</text></item><item><author>Denvercoder9</author><text>You&amp;#x27;re both correct, but USB Power Delivery, like so many things USB, is a total mess with different revisions, and versions of those revisions, that each extend and deprecate parts of the previous revision. I&amp;#x27;m going to ignore the actual protocol used for negotiation here, but there have also been at least three different protocols.&lt;p&gt;The first revision, rev 1.0, had six fixed power profiles: 5V&amp;#x2F;2A, 12V&amp;#x2F;1.5A, 12V&amp;#x2F;3.0A, 12V&amp;#x2F;5.0A, 20V&amp;#x2F;3.0A and 20V&amp;#x2F;5.0A. These were deprecated by rev 2.0, version 1.2, which instead introduced power rules at four fixed voltages, supporting power supplies with different output powers. The maximum supported currents by the specification were 5V&amp;#x2F;3A, 9V&amp;#x2F;3A, 15V&amp;#x2F;3A and 20V&amp;#x2F;5A. These power rules were retroactively named the Standard Power Range (SPR) in rev 3.1. That revision also added the Extended Power Range (EPR), which raised all the current limits up to 5A, but only when used with electronically marked cables. EPR also added power rules at 28V, 36V and 48V, again requiring (differently) marked cables and up to 5A. So 5V&amp;#x2F;5A is a valid option, but only when used with a USB PD rev 3.1 compatible power supply and cable.&lt;p&gt;Orthogonally to the fixed power rules, rev 3.0 introduced the Programmable Power Supply, which allows a configurable voltage between 3.3V and 21V in steps of 20 mV. This was extended by rev 3.1 with voltages between 15V and 48V in steps of 100 mV, called the Adjustable Voltage Supply. As far as I&amp;#x27;m aware this is not commonly used, and most products advertising Power Delivery support use the predefined power rules.</text></item><item><author>coder543</author><text>No, Wikipedia is looking like it&amp;#x27;s out of date or wrong. It’s &lt;i&gt;not&lt;/i&gt; a definitive source, especially for highly technical topics like this.&lt;p&gt;Here is another industry source which has a table that also says 5V at 5A: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.graniteriverlabs.com&amp;#x2F;en-us&amp;#x2F;technical-blog&amp;#x2F;usb-power-delivery-specification-3-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.graniteriverlabs.com&amp;#x2F;en-us&amp;#x2F;technical-blog&amp;#x2F;usb-po...&lt;/a&gt;&lt;p&gt;In fact, using Wikipedia’s sources, I found the actual specs and here is another piece of supporting evidence for these other articles:&lt;p&gt;&amp;gt; The Fixed PDOs Maximum Current field Shall advertise at least 3A, but May advertise up to RoundUp (PDP&amp;#x2F;Voltage) to the nearest
10mA. Requires a 5A cable if over 3A is advertised.[0]&lt;p&gt;This is a footnote attached to 5V3A, indicating to me that chargers are allowed to offer more than 3A at 5V.&lt;p&gt;At a minimum, the spec seems to be ambiguously written, but I’ve only spent a few minutes skimming it. Multiple industry sources (previously linked) believe that 5V@5A is within the spec, even without using PPS.&lt;p&gt;[0]: “USB_PD_R3_1 V1.8 2023-04”</text></item><item><author>KennyBlanken</author><text>It&amp;#x27;s not hard to find at all.&lt;p&gt;&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;USB_hardware#USB_Power_Delivery&quot; rel=&quot;nofollow noreferrer&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;USB_hardware#USB_Power_Deliver...&lt;/a&gt;&lt;p&gt;5v3A is the limit of USB PD SPR.</text></item><item><author>coder543</author><text>I don’t agree. I found this straightforward statement:&lt;p&gt;&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.anandtech.com&amp;#x2F;show&amp;#x2F;16712&amp;#x2F;usbc-power-delivery-hits-240w-with-extended-power-range&quot; rel=&quot;nofollow noreferrer&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.anandtech.com&amp;#x2F;show&amp;#x2F;16712&amp;#x2F;usbc-power-delivery-hit...&lt;/a&gt;&lt;p&gt;&lt;pre&gt;&lt;code&gt;    &amp;gt; USB-PD R3.1 supports three charging models:
    &amp;gt; - Fixed voltage
    &amp;gt; - Programmable power supply (PPS), and
    &amp;gt; - Adjustable voltage supply (AVS).
    &amp;gt; In the fixed voltage scheme, the Standard Power Range (SPR) mode supports 3A and 5A at 5V, 9V, 15V, and 20V.
&lt;/code&gt;&lt;/pre&gt;
That’s about as clear as it can be, assuming AnandTech is correct.&lt;p&gt;Also keep in mind the existence of PPS as another data point. I have an Anker charger sitting in front of me that offers 3.3V-11V at 5A. 5V at 5A falls squarely in that range, as long as you have an e-marked cable that can support 5A. (I have no idea if the Pi 5 supports negotiating PPS, but it would increase compatibility with chargers if it does.)&lt;p&gt;I agree the Pi 5 should have included a buck converter or something, but I don’t think it’s correct to say they’re not standards compliant. It’s just not a common use of the standard.</text></item><item><author>p1mrx</author><text>&amp;gt; It also supports USB-C Power Delivery, so finding a power supply that’s capable of supplying all that juice to the Pi 5 is a lot easier&lt;p&gt;Isn&amp;#x27;t this mostly false? The Pi4 uses 15W at 5V3A.  The standard says, to exceed 15W you should increase the voltage, but Pi5 increased the amperage instead.  5V5A USB-PD supplies are almost unheard of.&lt;p&gt;I wonder how much a 9V3A -&amp;gt; 5V5A buck converter dongle would cost.</text></item></parent_chain><comment><author>mschuster91</author><text>&amp;gt; I would actually prefer different shapes, because then you could be pretty confident that if everything fit it was going to work.&lt;p&gt;The baseline profiles for power delivery (i.e. anything up to 20V@5A) have been all but done for two, three years now - you can readily buy combinations of PD and MUX chipsets that handle &lt;i&gt;everything&lt;/i&gt; you can throw at them, and Anker has high-quality chargers to supply the juice.&lt;p&gt;The thing where USB-C still has issues is alternate modes. USBx usually works on all ports of a laptop or PC and virtually all cables, but anything involving TB, display, debug or audio is a hit-and-miss given how incredibly difficult it is to route all these high-frequency signals and properly mux them.</text></comment>