red pill V2

i’d re-ordered 3 off red pills, i got

apols for the pic, i struggled for quite a while to get it below 64k

they’ve very kindly messed with the swd connections, added a reset pin
last night i super glued my swd cables at each end – typical

boot links, now only a single header
button style has changed

added a 5v/tx/rx/gnd header

usb skt is a 2 point fixing plus tracks

underneath, it’s lost the big caps, now has 2 cylindrical crystals, one is 12mhz

top view with usb skt to the bottom
i tried to do this as 2 cols, as a table
i got the 2 bit right anyway

[td] vbat <==> vdd [/td] gnd <==> gndc13 <==> b9rst <==> b8gndA <==> b7vddA <==> b6a0 <==> b5a1 <==> b4a2 <==> b3a3 <==> a15a4 <==> gnda5 <==> a12a6 <==> a11a7 <==> a10b0 <==> a9b1 <==> a8b10 <==> b15b11 <==> b14gnd <==> b135v <==> b12

2015-09-23 11.50.15.png (57.66 KiB) Viewed 1048 times

oops, only saw the red/orange

and totally missed the GD32F103 board forum

No problem, it is indeed a GD32 based board, you should be able to flash the GD32 bootloader on it using the latest code in the repo. You will need to add the 1K resistor, as shown below to get it to re-enumerate correctly, but even without this, the board is usable. It is still work in progress so far as getting all of the peripherals working to the level of the STM32F103C8T6, but good progress is being made.

If I get a bit of spare time this week, I’m going to try to see what else I can test on the board.
BTW if you use images hosted on google images or elsewhere, you don’t need to worry about the 64K limit. My image above is hosted that way, and I think the google scaled down version is about 240K, the original is around 2Mb.

for some reason there’s a no entry icon in your post and no image?

btw its full code is gd32f103c8t6

i was in the process of BMP’ing a red pill, so when these arrived, red/orange
now i wonder … … … …

stephen

zmemw16 wrote:for some reason there’s a no entry icon in your post and no image?

Nope, the problem is that I’m an idiot and shared the wrong link. I also spotted that the resistor looks like 1K not 1.5K Should be working now, sorry for the confusion.

EDIT: The colours in the picture are a little unclear, so I fired my multimeter on the resistor, it measures 2K Ohm in circuit. but that would be Red, Black, Red (2K), Black (20%) surely… I think Its getting too late in the day for my brain… Unless… nope its a “5 band resistor” with four bands … Red, Black, Black, Brown, (None)… maybe… Roger?

Well, whatever it is, it works.

zmemw16 wrote:i’d re-ordered 3 off red pills…

it is and your ‘camera’ sees a lot better and clearer than mine

how does a 1k measure 2k in-circuit?
shouldn’t it always measure less, unless you’re not probing each end of said resistor;
anything else is in parallel with it.

stephen

I think it is actually a 2K resistor, but the colour bands are a little hard to fathom. I think it is a 5 band style resistor with 4 bands (i.e. band 5 is blank).
That makes the most sense on the Digikey resistor calculator. Red,Black,Black,Brown,(blank/none)
Unfortunately the problem with standards (in this case resistor colour codes) is that there are so many to choose from I believe my multimeter over my dodgy photography. In any case, since this is a pull up resistor, its exact value is not particularly critical. Anything from 1K to 100K would probably work, most of the time. The exact value only becomes critical if timing and/or current consumption are an issue. For the purposes of this exercise, close enough is good enough I suspect.

Where did you get the GD32 boards?

http://www.aliexpress.com/item/Compatib … 81383.html

currently ￡5.29 ukp (￡ 3.67 X3)

more than i thought/remembered

stephen

Andy

It’s a 2k resistor. But its a four band one. I just happened to have a load of them. So I thought I may as well use some of them on the gd32 boards.

My local electronics shop seems to mainly sell 4 band resistors, which I find hard to read. As I’m more usred to 3 band ones.

But anything between 1.5k and 4.7k seems to work on for the USB D plus pullup. We