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UART connection between ATSAMD20 and ATtiny4313
inI'd like to use async UART to let these MCUs communicate. The protocol will be request-response with the request generated by the SAM MCU. The...
I'd like to use async UART to let these MCUs communicate. The protocol will be request-response with the request generated by the SAM MCU. The baudrate will be 38400bps. I'd like to use internal oscillator of ATtiny4313, while the SAM will use an external 32.768kHz crystal (that is multiplied by internal PLL to reach 48MHz). I'm not sure if this scenario can work well. My concerns are...
PID controller with a limited range of control variable
inIn one application an AC voltage sourced by a generator is applied to a load as a PWM waveform. The period PER is fixed (for example, 100ms) and...
In one application an AC voltage sourced by a generator is applied to a load as a PWM waveform. The period PER is fixed (for example, 100ms) and the pulse-width PW has a maximum (for example, 20ms). The user can change the voltage peak (and consequently the voltage RMS) by an handle, while the controller manages automatically the PW. The load changes its temperature when the PWM wavefo...
How to snif full-duplex UART protocol between two nodes
inMany times I need to snif and log on a file the activity between two nodes that talk over a full-duplex UART (separate TX and RX lines). Just...
Many times I need to snif and log on a file the activity between two nodes that talk over a full-duplex UART (separate TX and RX lines). Just an example, consider a host MCU that talks with a modem through AT commands. It's a half-duplex protocol because the MCU sends the AT command and the modem replies. However the modem is able to send URC messages that can be emitted at any time. ...
SPI Quad Serial Flash: two "quad" modes?
inI'm studying datasheet of SST26VF080A. It's a SPI Quad Flash memory in standard 8 pin package. I'm not sure I correctly understood the quad...
I'm studying datasheet of SST26VF080A. It's a SPI Quad Flash memory in standard 8 pin package. I'm not sure I correctly understood the quad mode. It appears to me two quad modes are supported: SPI Quad mode (IOC=1 in Configuration Register) and SQI mode (after sending Enable Quad I/O command). For example, after setting IOC bit in Configuration Register I can use SQOR command (SPI Qu...
Improved display in Google Groups
inI found this browser extension to let you apply formatting codes to any page. It can be used to apply a monospaced font to Google Groups, which...
I found this browser extension to let you apply formatting codes to any page. It can be used to apply a monospaced font to Google Groups, which will help viewing tables and even ASCII art that people post. I had always thought GG stripped excess white space, like tabs, multiple spaces, blank lines. But it seems that's not correct, they are all there, just not shown naturally.
Text on FSM
inHello Does anyone know of a nice text on finite state machines and their software implementation on embedded systems? I'm looking for some...
Hello Does anyone know of a nice text on finite state machines and their software implementation on embedded systems? I'm looking for some theoretical background and design methodology. A few examples of "C" implementation would be a nice but not really needed. I'm not looking for a recipe or code but for a more formal explanation on the workings of FSM. Thanks jmariano
Boxed MCU with RS-232 Port
inThe unit only really needs one serial port, but it is more convenient to have two connectors, so I guess it needs to ports. One port will only...
The unit only really needs one serial port, but it is more convenient to have two connectors, so I guess it needs to ports. One port will only receive and the other only transmit, no handshaking. The function is pretty simple. A sensor sends a line of about 50 chars, at 9,600 bps, once per second. This box counts 20 lines and adds a header. So nothing fancy is required of the MCU. There ...
Half-duplex RS485: simple auto-direction solution
inI think you already know this trick: connect DE/RE signals of RS485 half-duplex transceiver to TX *negated* signal from UART and connect TX...
I think you already know this trick: connect DE/RE signals of RS485 half-duplex transceiver to TX *negated* signal from UART and connect TX input of transceiver to GND. If the bus is not driven by anyone, A signal goes high and B signal goes low thanks to the pull-up/down resistors. The trick uses the fact that the undriven bus and transmitting 1 is the same thing: A is high and B is...
Touchpanel I/O
inI am amazed at how commonplace this is becoming -- and how shortsighted the implementations! Have YOU considered how a user CLEANS the...
I am amazed at how commonplace this is becoming -- and how shortsighted the implementations! Have YOU considered how a user CLEANS the panel? If the device can be turned OFF, then they could resort to that avenue to ensure cleaning actions aren't interpreted as "commands". But, if it *can't* be (or, if the user decides they want to clean the panel NOW -- for whatever reason), then yo...
Another STM32F103 clone?
inI have bought few Blue Pills on Aliexpress. I expected to receive boards with some of known clones. But what I get does not look like any...
I have bought few Blue Pills on Aliexpress. I expected to receive boards with some of known clones. But what I get does not look like any clone that I have heard of: - Cortex M4 with no FPU - 32k RAM - 128k flash - set of devices like STM32F103C8T6 Chip seems to be resonable compatible, but I noticed notable difference in I2C peripherial: bit 14 in OAR1 (own address register 1) se...
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