About mckenney

mckenney · 2022-08-03

We are considering using an array (>2) of LPS22CH devices on a single I2C bus, and intend to use SA0 as (in effect) a Chip Select. We would like to know whether SA0 is polled (a) once at startup or (b) on every Start condition [we need (b)]. DT0132 a...

mckenney · 2023-05-15

They are used/configured in the BSP, e.g. stm32wlxx_nucleo_radio.[c/h]. Look for RF_SW_CTRL1_PIN (and similar).The usage is different between the MB1389 (Nucleo) and MB1842 (i4s) reference designs. MB1842 has its own BSP.

mckenney · 2023-03-06

By using a voltage divider it's very easy to introduce a high source impedance, which prevents the sampling capacitor from fully charging.> hadc.Init.SamplingTime = ADC_SAMPLETIME_3CYCLES_5;3.5 cycles is pretty short. Data sheet [DS10668 rev 6] Tab...

mckenney · 2022-08-05

Yes. On an idle bus, all the devices have (e.g.) SA0=0 (address 0x5C). To talk to one of the devices, the host sets its SA0=1, and sends the request to address 0x5D.This "trick" only works if the device actively monitors its SA0 (b) rather than fetch...

mckenney · 2020-10-09

Thank you. I was looking for exactly this today.It does seem like the Product folder would be a better place for it, but I'll take what I can get.

mckenney · 2020-08-06

"&array1[0xEB]" (in context) generates an odd address, so a 16-bit access is unaligned.Per DUI0497A Sec 3.3.4: "There is no support for unaligned accesses on the Cortex-M0 processor. Any attempt to perform an unaligned memory access operation results...

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