Search found 119 matches

by chuckbook
Sun Jun 28, 2020 2:32 pm
Forum: Pyboard D-series
Topic: PYBD WBUS connector
Replies: 20
Views: 2361

Re: PYBD WBUS connector

When using small mezzanine connectors it is good practice to route unused pins to dummy tracks with vias close to the unused pads.
by chuckbook
Wed Jun 24, 2020 10:23 am
Forum: MicroPython pyboard
Topic: vbat connection solution ?
Replies: 7
Views: 339

Re: vbat connection solution ?

The VBACK pin has to be used for RTC backup.
by chuckbook
Mon Jun 22, 2020 9:34 am
Forum: Pyboard D-series
Topic: Max number of files to iterate with os.listdir()
Replies: 10
Views: 334

Re: Max number of files to iterate with os.listdir()

FAT filesystem has a terrible performance with more than some thousands of entries per directory.
Try to use a multi level hierarchy with less than 1000 entries per directory.
by chuckbook
Thu Jun 11, 2020 12:15 pm
Forum: Pyboard D-series
Topic: PYBD WBUS connector
Replies: 20
Views: 2361

Re: PYBD WBUS connector

If a PYBD doesn't 'click' into position there is no guarantee for proper contact of all pins.
Although HIROSE only specifies 30 mating cycles (-35° to 85° C), the connectors will easily withstand more than 1000 cycles at room temperature.
by chuckbook
Mon May 18, 2020 8:00 am
Forum: Pyboard D-series
Topic: Emulation of multiple I2C slaves with a Pyboard D-series
Replies: 2
Views: 272

Re: Emulation of multiple I2C slaves with a Pyboard D-series

STM32F7xx supports two slave addresses in HW plus one broadcast (ADDR 0). MP currently supports only one slave address.
by chuckbook
Tue May 12, 2020 3:41 pm
Forum: Pyboard D-series
Topic: Flash ROM, external QSPI, v1.1 vs. D's three variants
Replies: 3
Views: 288

Re: Flash ROM, external QSPI, v1.1 vs. D's three variants

PYBV11 has 1024kB of internal flash. Due to the it's sector organization only 112kB can be used as FAT filesystem. The FAT area consists of one 3*16kB and 1*64kB sectors. As flash can only erased sector wise, a RAM buffer is needed for buffering content. PYBV11 reserves 64kB of SRAM for this purpose...
by chuckbook
Sun May 10, 2020 3:10 pm
Forum: Pyboard D-series
Topic: PYBD WBUS connector
Replies: 20
Views: 2361

Re: PYBD WBUS connector

According to Hirose specs the four extra pins on the 40 pin connectors are only for mechanical stability. They can't be used as extra contacts.
by chuckbook
Tue May 05, 2020 2:33 pm
Forum: Pyboard D-series
Topic: Choosing between powering options.
Replies: 4
Views: 393

Re: Choosing between powering options.

Power requirements are defined by these components: Wireless Module (Murata 1DX) The Wireless Module uses an internal linear regulator for the wireless transmitter. See Murata datasheets for the specs. ADC Reference ADC performs best with a stable +3.3V reference voltage which is provided with a pro...
by chuckbook
Fri Feb 21, 2020 9:43 am
Forum: General Discussion and Questions
Topic: Serial binary data packets using COBS and uasyncio
Replies: 6
Views: 499

Re: Serial binary data packets using COBS and uasyncio

Would it make senses to use either 3964 or 3964R protocol?
by chuckbook
Thu Jan 16, 2020 11:57 am
Forum: Pyboard D-series
Topic: Pyboard D RTC accuracy
Replies: 5
Views: 1099

Re: Pyboard D RTC accuracy

This sounds too good to be true. Doesn't the DS3231 datasheet claim +/-2 ppm which (roughly) means +/-1 min/a?
Anyhow, this is still a very good result.