Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [mcp23s17]

10 questions
3
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1 answer

Pressing one key in a button matrix reads all keys in that column

I'm using an MCP23017 IO Expander to make a button matrix (4x4). //Defines for Matrix Rows/Columns #define ROW0 0x10 #define ROW1 0x20 #define ROW2 0x40 #define ROW3 0x80 #define COL0 0x01 #define COL1 0x02 #define COL2 …
Cros Dude
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2
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1 answer

MCP23017 open drain interrupts not working as expected

I have multiple MCP23017 ICs with their interrupts all connected in serial. The interrupt pins are configured to be open-drain. All the A port interrupt pins are connected together and all the B port interrupt pins are connected together. When I…
P4rk
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1 answer

Why is the MCP23S17 device getting too hot suddenly and randomly?

Circuit is a Raspberry Pi 4A SPI master node talking with one MCP23S17 device. I'm testing the single-circuit version in a protoboard. We are using A bank GPIOs for reading, and B bank GPIOs for writing. From them, two GPIOs will be used with wires,…
Suvi_Eu
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MCP23S17 IOCON register values do not update correctly

I am currently testing the functionality of a Microchip MCP23S17 SPI 16-bit GPIO port expander for an application with a number of external inputs & outputs. The initial configuration of an MCP23S17 has been keeping me busy with quite a struggle for…
wave.jaco
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MCP23017 link to an optocoupler Rail input

In my project I have an optocoupler Rail 32 units like the proto below . I want to link it to my MCU with 2 mcp23017 digital Input . Do I need to put a Schmitt Trigger before the mcp23017 to have a perfect electronic PCB signal as i have a common…
Khales Naim
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0
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1 answer

MCP23017 INT Pin always high - INT cannot be cleared

trying to enable INT on MCP23017 so that, in case of a state change on any PIN from Port A (e.g from low to high) an interrupt should be triggered on INTA. Unfortunately the INTA pin remains high as long the pin on port A is high. So I can not clear…
D.S
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1 answer

MCP23S17 - do I have to use both Chip Select and Hardware Addressing?

I've used MCP23S17 before. 6 of it and I just used Chip Select. Hardware address pins all 0. https://ww1.microchip.com/downloads/en/DeviceDoc/20001952C.pdf In datasheet, hardware addressing can be used to connect 8 of it in a bus. No problem. Now, I…
Ariel Narboada
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1 answer

Connecting loads to an MCP23S17 GPIO outputs

I would like to connect various MCP23S17 datasheet devices to the Raspberry Pi3 MB SPI port. But first I would like to start making some test with a single connection: only one chip. After this I will add more than one expanser to the SPI net. First…
Suvi_Eu
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1 answer

What about MCP23S17 GPIO pins output ports being also used to be read by input pins?

We are connecting Raspberry Pi3B with some MCP23S17 expanders: MCP23S17. I have read that they could emulate an open-drain outputs, playing with high Z state of the pin when configured as input. What kind of input and output those GPIOs are? What…
Suvi_Eu
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Does a Mcp23s17 output pin keep the value after being unselected?

I'm designing a SPI based communiations circuit between Raspberry Pi4+B as a master and (n x 8) GPIO expander modules, as slaves. Concretely we have selected an MCP23S17 GPIO expander: Datasheet By the moment I will try if the system is able to…
Suvi_Eu
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