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  • 03:22
    jaxxzer commented #1100
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  • Sep 16 02:46
    jaxxzer commented #1100
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  • Sep 12 10:06
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    jaxxzer edited #1100
[skiboy, irc.freenode.net] it's the cheapest ARM chip I've seen, so it would be good for OSHW projects that need to go to the hundreds or thousands of units.
[karlp, irc.freenode.net] laughs
[karlp, irc.freenode.net] if it doesn't have a register to say it's stabilized do you need to wait at all?
[karlp, irc.freenode.net] what do the docs say?
[karlp, irc.freenode.net] how are you going to decide how long to waait for?
[skiboy, irc.freenode.net] The docs say nothing, however the official library waits for 10000
[skiboy, irc.freenode.net] I only discovered the officail library once I was done writing pretty much everything
[skiboy, irc.freenode.net] And it remarked that it needed time to stabilize.
[skiboy, irc.freenode.net] Though I kind of feel that this wouldn't be a good way to do it
[skiboy, irc.freenode.net] If we assume that the 10000 nops are for its top clock of 36mhz
[skiboy, irc.freenode.net] Then it wouldn't need to wait as long at 290khz, which is apparently as low as it can go, if my math is correct
[skiboy, irc.freenode.net] The datasheet is weird in a number of aspects.
[skiboy, irc.freenode.net] There seems to be some sort of comparator/amplifier, but it is completely undocumented.
[skiboy, irc.freenode.net] I think they probably couldn't get it to work up to spec, so they just nuked it.
[skiboy, irc.freenode.net] I've seen similar things with the GD32, where you can overclock them, but it isn't documented.
[skiboy, irc.freenode.net] The comparator was going to be interrupt number 3, and it still is, but the comparator is almost totally undocumented, including what pins were going to be used for it.
[karlp, irc.freenode.net] 10000 whats?
[skiboy, irc.freenode.net] 10000 loops of an empty for loop
[skiboy, irc.freenode.net] The clock isn't even that accurate anyway. It's internal only and is +-1%
[karlp, irc.freenode.net] that's plenty accurate.
[karlp, irc.freenode.net] avrs are +- 10%
[skiboy, irc.freenode.net] for basic tasks, yes
[skiboy, irc.freenode.net] holy moly
[skiboy, irc.freenode.net] I didn't know AVRs were that off
[karlp, irc.freenode.net] it's actuaslly more than accurate for most things.
[karlp, irc.freenode.net] it doesn't actually matter for most stuff.
[karlp, irc.freenode.net] if the uart periphs do oversampling, and most of htem do, 1% is _plenty_
[skiboy, irc.freenode.net] Yeah, that makes sense
[skiboy, irc.freenode.net] I have access to a pick-n-place and reflow ovens now where I work, so getting the BOM cost down is important to me, and I hope other people can use this quirky chip in their projects as well.
[karlp, irc.freenode.net] I think you're massively overstating the impact of the cpu on the total assembled cost,+
[karlp, irc.freenode.net] +nre
[karlp, irc.freenode.net] but whatever floats your boat :)
[karlp, irc.freenode.net] I'll get an email when your PR lands :)
[skiboy, irc.freenode.net] Actually, I was wrong. The device can clock as low as 17khz
[skiboy, irc.freenode.net] I missed a nybble in my math
[skiboy, irc.freenode.net] At that point, I don't know why you wouldn't just put it into sleep mode
Matthew weger
Hey my timer for an encoder isn't incrementing and i'm not sure why on the stm32f0 its something with my config
[karlp, irc.freenode.net] w-m-d: we'll need more details :)
Jacob Walser
Hi everyone
Anyone using stm32g4 yet?
I am trying to program with openocd using this patch http://openocd.zylin.com/#/c/4807/
But run into a problem:
openocd -f interface/stlink.cfg -f target/stm32g4x.cfg -c "program debug.elf verify reset exit"
Open On-Chip Debugger 0.10.0+dev-00926-g434cf2f8 (2019-08-31-13:39)
Licensed under GNU GPL v2
For bug reports, read
Info : auto-selecting first available session transport "hla_swd". To override use 'transport select <transport>'.
Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD
Info : clock speed 2000 kHz
Info : STLINK V3J2M1 (API v3) VID:PID 0483:374E
Info : Target voltage: 3.300997
Info : stm32g4x.cpu: hardware has 6 breakpoints, 4 watchpoints
Info : Listening on port 3333 for gdb connections
Info : Unable to match requested speed 2000 kHz, using 1000 kHz
Info : Unable to match requested speed 2000 kHz, using 1000 kHz
target halted due to debug-request, current mode: Thread 
xPSR: 0x01000000 pc: 0x08000318 msp: 0x20004000
Error executing event reset-init on target stm32g4x.cpu:
embedded:startup.tcl:214: Error: 
in procedure 'program' 
in procedure 'ocd_process_reset' 
in procedure 'ocd_process_reset_inner' called at file "embedded:startup.tcl", line 214
Error: jtag status contains invalid mode value - communication failure
Polling target stm32g4x.cpu failed, trying to reexamine
Examination failed, GDB will be halted. Polling again in 100ms
** Programming Started **
Info : Previous state query failed, trying to reconnect
Error: jtag status contains invalid mode value - communication failure
Polling target stm32g4x.cpu failed, trying to reexamine
Examination failed, GDB will be halted. Polling again in 300ms
Error: can't get device id
Error: auto_probe failed
** Programming Failed **
shutdown command invoked
Brian Viele
Does anyone have any experience bringing up an stm32h743 with libopencm3? Hoping it shares significant mapping with f4/f7, and main effort will be related to update linker script, some PLL customization, additions to init for cache and MPU, and compiler flag tweaks. I see g8 support being explicitly added, but not much with regards to h7.
Chuck McManis
Hey @jaxxzer I've been doing some work with the G4 but using the 'copy the hex file to the fake disk' mode rather than trying to get OpenOCD to talk to it just yet. Have you considered downgrading the STLink on board to V2-a which is well supported by OpenOCD?
Matthew weger
for the timers in libopencm what is the timer input and what's the timer pin. I'm confused by the documentation. It says "source" but source means so many different things.
Matthew weger
nvm i got it working by rerouting the trace
Can someone explain to me how EXTI interrupts work in libopencm ? the examples are really lacking. I got them working really well in modm
Matthew weger
I am trying to build the blackmagic probe firmware for the F4discovery board using the latest version of libopencm3. I get an error indicating that the function "timer_reset()" is missing. I looked at the timer code for the STM32F4 and indeed the function is no longer there. What happened to it and what is the recommended replacement?