Search found 15 matches

by EntropyWizard
Mon Feb 11, 2019 7:20 pm
Forum: Custom design boards
Topic: Small STM32F103TBU6 Development Board
Replies: 0
Views: 278

Small STM32F103TBU6 Development Board

I've been experimenting with the design of a small development board for various projects. This is my latest version for the STM32F103 (and STM32F101) series chips in the VFQFPN 36 6x6mm package. I wanted a 2-layer board with components on one side so it would be cheap to produce and easy to bake at...
by EntropyWizard
Tue Oct 30, 2018 2:01 pm
Forum: Off topic
Topic: No cost Wireless UART
Replies: 8
Views: 539

Re: No cost Wireless UART

This is very interesting! I'm no radio expert, but it seems that 36MHz is also used for some RC cars and may be usable. What are the reasons 27MHz was picked? 36MHz would be easier to generate on MCO as it is SYSCLK/2, rather than looking for a 6.75 MHz crystal.
by EntropyWizard
Sat Sep 29, 2018 6:58 pm
Forum: Let us know a bit about you and your projects
Topic: STM32F103 CUSTOM BOARD - USB ISSUES
Replies: 12
Views: 574

Re: STM32F103 CUSTOM BOARD - USB ISSUES

Before you go to all the work of adding a reset circuit, and making a new board, it may be worth working with your current one a bit more. Based on your schematic, if you have also added the 1.5k pull-up to 3V3, it _should_ work. Roger and others have added code to support the blue pill's minimal US...
by EntropyWizard
Tue Sep 25, 2018 3:40 pm
Forum: General discussion
Topic: [SOLVED]millis() from different BluePills is drifting a lot
Replies: 30
Views: 1432

Re: millis() from different BluePills is drifting a lot

Another angle you can use to track down this issue: Configure your MCO pin on the micro (pin A8) to output your system clock on each board, then measure the output with a counter or oscilloscope. This will verify both that your crystal is working, and that your clock configuration is correct.
by EntropyWizard
Sun Sep 16, 2018 3:51 pm
Forum: General discussion
Topic: [SOLVED] Record variables??
Replies: 17
Views: 749

Re: Record variables??

Since you indicate you will be using the RTC, I assume you plan to power VBAT to keep the RTC running when you are otherwise shutdown. If you look at chapter 6 of the reference manual, there are some backup registers for user applications. They are not EEPROM, but they might work for you, as long as...
by EntropyWizard
Wed Jun 13, 2018 4:09 pm
Forum: PR's bugs and enhancements
Topic: [FEATURE] Bootloader JTAG-SWD Pin Configuration (use PA15 for USB reset)
Replies: 0
Views: 513

[FEATURE] Bootloader JTAG-SWD Pin Configuration (use PA15 for USB reset)

I'm working with a small custom STM32F103 based board attempting to use A15 as USB hardware reset and ran into an issue. While core sketch initialization disables the JTAG-SWD subsystem and enables AFIO, it seems the bootloader does not. This means that the ports PA13, PA14, PA15, PB3, & PB4 can be ...
by EntropyWizard
Tue Jun 12, 2018 3:46 pm
Forum: General discussion
Topic: Programming a barebones STM32F205
Replies: 7
Views: 689

Re: Programming a barebones STM32F205

Hey, welcome to the forum. It might be easier to start with a STM32F103 series chip, as there is a lot more support and general knowledge around that one. Your ST-Link should work fine with 4 wires as mentioned, I only ever use 3 - the ground and SWDIO, SWCLK. The ROM loader should also work, even w...
by EntropyWizard
Thu May 10, 2018 7:47 pm
Forum: STM32F103 Boards
Topic: Inverse LED
Replies: 4
Views: 312

Re: Inverse LED

It's quite common to wire LEDs active low so the port can be configured as open drain. That is how the common "vcc-gnd" brand blueblue pills are configured. Maybe your original board was different?
by EntropyWizard
Tue May 01, 2018 4:53 pm
Forum: Maple & Maple mini etc
Topic: Steady Clock output MCO 32 Mhz
Replies: 9
Views: 703

Re: Steady Clock output MCO 32 Mhz

The MCO output should be very consistent. A couple of things to check. Make sure that pin PA8 is in 50MHz mode. The ST32 has lower drive 2 MHz and 10 MHz modes. If you are trying to drive it to 3.3 V, you want it in push-pull mode. If you are trying to pull it toward 5 V with a pull-up resistor, you...
by EntropyWizard
Sat Apr 21, 2018 2:31 pm
Forum: Builds and Announcements
Topic: BluePill bootloader updated to use boot1 as the button
Replies: 12
Views: 3268

Re: BluePill bootloader updated to use boot1 as the button

Neat idea! Can you clarify one thing... the BOOT1 pin is also used to select SRAM boot space. I'm guessing its important to set ONLY the BOOT1 pin when you want continuous DFU mode. If both BOOT0 and BOOT1 were selected, the micro would try to boot to SRAM. Is it correct to say that we would use eit...