HIDman AXP
January 2025
The HIDman AXP is described on the GitHub web page at here.
I had PCBWay assemble/build a PCB for me (PCB + soldered-on components). It arrived, and I went through the process of downloading the firmware (version 1.1.4) onto it.
Some notes of my experience follow. You will read that a firmware upgrade is required to get IBM 5160 (IBM XT) support.
NOTE: Do not confuse the HIDman AXP with other HIDman products. E.g. HIDman PS/2. E.g. HIDman mini.
Revisions
There have been some hardware changes. At this time (DEC24), the PCB is at revision C. ("HIDMAN AXP rev c" is printed on the PCB underside.)
Accordingly, there is a new 'front enclosure plate', one to cater for the LED now being directly under the switch (not as shown in the first photo at here).
PCBWay
The minimum PCB count is five, and so what I had to order was five PCB's, plus components for one PCB, plus assembly, plus postage. (I did not balk at five PCB's, because $1 per PCB is cheap.)
Part way through assembly, I received an email from PCBWay containing photos, asking me to verify that the components were oriented correctly on the partially soldered PCB. Upon receiving verification, they would proceed with assembly/build.
They also pointed out a discepancy about C1 and C12. But that was of no concern because C1 and C12 are electrically the same, and being MLCC, have no polarity.
I found a decent photo online (this photo) of the HIDman AXP (revision 2), and used that to verify to PCBWay that all looked good.
On the assembled/built PCB that arrived from PCBWay, the soldering is well done. My PCB is green with white silkscreen (printing), which I think were the default selections when I ordered. Photo at here.
After receiving my assembled/built PCB, I needed to download the firmware onto it.
Later, I may look at getting the aluminium case and front+rear plates. We will see. The case (black or unpainted) can be purchased cheaper at multiple places.
Below, I will refer to my assembled/built PCB as 'unit'.
11FEB25 update:
I did later acquire the aluminium case, but an unpainted one from eBay. And to go with that, from PCBWay, white coloured front+rear plates with black printing ("Solder mask: White, Silkscreen: Black"). Photo at here.
Discrepancies
• On the BOM (bill of materials) at the GitHub site, resistor network RN3 is listed as 150 ohms. PCBWay's BOM shows 120 ohms instead, and 120 ohms is what PCBWay fit. RN3 is used to control the brightness of the the LED, and so the 120-versus-150 difference was not a concern to me.
• As mentioned earlier, PCBWay pointed out a discrepancy about C1 and C12. See here. It was of no concern because C1 and C12 are electrically the same, and being MLCC, have no polarity.
Keyboard emulation: Switching between the three modes
After I downloaded the firmware into my unit, I saw that the front panel LED turns on when the unit receives power.
At each momentary push of the 'keyboard mode' button, the unit cycles between three different keyboard emulation modes and the colour of the LED indicates the mode. See this.
I notice that when the HIDman AXP gets powered, it 'remembers' the keyboard emulation mode that it was in when it got lost power.
Keyboard emulation: Trying with IBM 5150 (IBM PC)
Keyboard emulation mode is 'XT' (AXP's front panel LED is orange).
Connection photo at here.
11FEB25 update:
If firmware release v1.1.5 (or later) is not on the HIDman AXP, a 301 error (keyboard not responding to soft reset request) will be displayed by the 5150's power-on self test (POST).
v1.1.5 has yet to be released, but a beta of that, version v1.1.5f, is available to download at the GitHub web page for the HIDman AXP - see here.
Keyboard emulation: Trying with IBM 5160 (IBM XT)
Keyboard emulation mode is 'XT' (AXP's front panel LED is orange).
Connection photo at here.
11FEB25 update:
For the HIDman AXP to work with the IBM 5160 (fitted with IBM BIOS ROM's on the motherboard), the HIDman AXP needs to contain release v1.1.5 (or later).
v1.1.5 has yet to be released, but a beta of that, version v1.1.5f, is available to download at the GitHub web page for the HIDman AXP - see here.
Keyboard emulation: Trying with IBM 5170 (IBM AT)
Keyboard emulation mode is 'AT' (AXP's front panel LED is blue).
The keyboard emulation works for me.
Fuse
The PCB has a 500 mA fuse at a certain location on the +5V line.
Note that one possible scenario for that fuse blowing, is if both of the following is accidentally done at the same time:
• Unit connected to the keyboard port on the vintage computer; and
• USB port on the unit connected to a modern computer.
In that scenario, the unit is receiving two different sources of +5V.
The fuse could blow if there is a slight voltage difference between the two sources.