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by tlfong01
Tue Mar 05, 2019 1:29 am
Forum: HATs and other add-ons
Topic: I2C I/O PORT EXPANDER QUESTION
Replies: 37
Views: 3739

Re: I2C I/O PORT EXPANDER QUESTION

... a Raspberry board has 2 SPI individual ports. Is there anyway to use 8x MCP23S17 on each of them? Using MCP23017 GPIO Pins to Select MCP23S17 Chips ... my old post on MCP23017 Demuxing . RE: RPI ZERO W MULTIPLE SENSORS - tlfong01 2019-Feb-13 https://www.raspberrypi.org/forums/viewtopic.php?f=91&t=233311#p1429189 ...
by tlfong01
Wed Jan 23, 2019 9:13 am
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

... But then I found the weight sensor HX711 very interesting, so I did some research, and try to test the device, using ESP8266, MCP23017, and then MCP23S17. I found it hard to test HX711, so even I tried different approaches, and sadly all ended up in failures, because I made too many newbie mistakes. ...
by tlfong01
Fri Dec 28, 2018 7:04 am
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

The only conclusion is that my [MCP23S17/MCP23S08] program is bad! Using SPI signals to directly control HX711 Let me walked through my failures so far (2018nov24 to now). 1. HX711 requires 25, 26, or 27 pulses as input. The specified clock ...
by tlfong01
Thu Dec 27, 2018 2:39 pm
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

MCP23S17 / MCP23S08 Pair Programming Notes Now I am testing S17 and S08 together, in sort of ... check out tomorrow. Mcp23s08 Test Program ( uploaded to my github! ) https://github.com/tlfong01/mcp23x17/blob/master/mcp23s17_2018dec2702.py ...
by tlfong01
Thu Dec 27, 2018 12:43 pm
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

tlfong01 wrote:
Wed Dec 26, 2018 12:28 pm
MCP23S17 / MCP23S08 Pair Programming Notes
Now I am testing S17 and S08 together, in sort of pair programming mode, for easy swap troubleshooting and cross checking.
...

MCP23S08 on Bread Board
...
by tlfong01
Wed Dec 26, 2018 12:28 pm
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

Now I have wired another MCP23S17 chip on a bread board for easy swap testing.[/i] On second thought, perhaps I should first check out the 8-bit MCP23S08, to make sure that I have not mixed up MCP23S17's 8bit/16bit Band0/Band1 names. ...
by tlfong01
Wed Dec 26, 2018 2:57 am
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

... another SPI device, I think I better write another function, blink the mcp23s17 Gpio ports , just to make sure I can at least write to the registers ... :mrgreen: My GitHub [ 2019 New Year Resolution! ] https://github.com/tlfong01/mcp23x17/ AliExpress MCP23S08/008 https://www.aliexpress.com/store/product/Free-Shipping-MCP23S08-E-SS-MCP23S08-I-SS-MCP23016-I-SO-MCP23017-I-SO/1395137_32247127139.html ...
by tlfong01
Tue Dec 25, 2018 2:29 pm
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

Tidying up messy SPI and MCP23S17 test functions[/b] Instead of starting trying another SPI device, I think I better write another function, blink the mcp23s17 Gpio ports , just to make sure I can at least write to the registers correctly, ...
by tlfong01
Tue Dec 25, 2018 1:34 pm
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

reading register IPOLA failure I will search my junk box to find any other SPI devices to check out. Tidying up messy SPI and MCP23S17 test functions In the mean time I am tidying up the messy group of spi and mcp23s17 test functions. I have placed the test functions in two layers: Layer ...
by tlfong01
Tue Dec 25, 2018 8:46 am
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

MCP23S17 reading register IPOLA failure Now I am repeatedly writing something to IPOLA and reading it back. But I always get the unexpected result of 0x7f. I swapped another MCP23S17 but still no luck. Reading MCP23S17 IPOLA ...
by tlfong01
Tue Dec 25, 2018 8:02 am
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

MCP23S17 reading register IPOLA failure Now I am repeatedly writing something to IPOLA and ... hex(recvByteArray[1]), hex(recvByteArray[2])) return ... # mcp23s17_2018dec2504.py tlfong01 2018dec25hkt1439 *** # $ hostnamectl = raspberrypi Raspbian GNU/Linux 9 (stretch) ...
by tlfong01
Sat Dec 22, 2018 2:51 pm
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

tlfong01 wrote:
Fri Dec 21, 2018 2:25 pm
Setting up MCP23S17

SPI MCP23017 Device Addressing Notes

...
by tlfong01
Fri Dec 21, 2018 2:25 pm
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

tlfong01 wrote:
Fri Dec 21, 2018 1:52 pm
Next step is testing MCP23S17

Setting up MCP23S17
...
by tlfong01
Fri Dec 21, 2018 1:52 pm
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

... testLoopbackThreeBytes(),.... sendBytes = 0x55 0x77 0x88 recvBytes = 0x55 0x77 0x88 End testLoopbackThreeBytes(),.... ''' Next step is testing MCP23S17 ... # *** spi012018dec2105.py 2018dec21hkt2142 *** # # Program Function # ---------------- # This program has the following test functions: ...
by tlfong01
Tue Dec 18, 2018 1:51 pm
Forum: Automation, sensing and robotics
Topic: Relay Module KY-019 5V
Replies: 488
Views: 98095

Re: Relay Module KY-019 5V

... resistances of about 900R x 8 is not noticeable. The load cell calibration is now complete. Next step is going back to python programming of SPI MCP23S17 to control HX711. SPI Testing Notes https://www.raspberrypi.org/forums/viewtopic.php?f=37&t=227137&p=1403249#p1403249 ...
by tlfong01
Mon Dec 17, 2018 3:24 am
Forum: Beginners
Topic: Detect current on Raspberry pi
Replies: 88
Views: 10251

Re: Detect current on Raspberry pi

... in inductance and feedback is far from adequate to understand what is going on. I don't even know where to start a wild guess. Rpi/Esp8266/Mcp23S17 GPIO Controlled Smart Buzzer Newbie Design Notes / to continue, ... Appendices - Prerequisites - Mutual Inductance Oliver Heaviside - Wikipedia ...
by tlfong01
Mon Dec 10, 2018 9:17 am
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

tlfong01 wrote:
Mon Dec 10, 2018 8:56 am
MCP23S17 Testing Notes
SPI Driver Installation Checking Notes
SPI Wiring Checking Notes

Rpi SPI Repeat Send One Character Waveform Checking Notes

...
by tlfong01
Mon Dec 10, 2018 8:56 am
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

tlfong01 wrote:
Mon Dec 10, 2018 6:39 am
tlfong01 wrote:
Sun Dec 09, 2018 1:28 pm
MCP23S17 Testing Notes
SPI Driver Installation Checking Notes

SPI Wiring Checking Notes
...
by tlfong01
Mon Dec 10, 2018 6:39 am
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

MCP23S17 Testing Notes SPI Driver Installation Checking Notes Python Module - Petrockblog https://github.com/petrockblog/RPi-MCP23S17 This Python module abstracts the GPIO expander MCP23S17 for usage on the Raspberry Pi. ...
by tlfong01
Sun Dec 09, 2018 1:28 pm
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

... Operating Conditions) To ensure the high-impedance state during power up or power down, OE should be tied to GND through a pulldown resistor; MCP23S17 Testing Notes StackOverflow/StackExchange mcp23017/mcp23s17 search results StackOverflow search results found containing mcp23017 - 55 results ...
by tlfong01
Sat Dec 08, 2018 2:58 pm
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

So I have decided to give up I2C MCP23017, and divert to SPI MCP23S17 [/i][/color] Quad SPI Mux Level Converter Board assembly notes TXS0104E 4-Bit Bidirectional Voltage-Level Translator for Open-Drain and Push-Pull Applications http://www.ti.com/lit/ds/symlink/txs0104e.pdf ...
by tlfong01
Sat Dec 08, 2018 8:45 am
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

tlfong01 wrote:
Sat Dec 08, 2018 4:06 am
Replacing I2C MCP2307 by SPI MCP23S17
I have been thinking of using Rpi software I2C, but found the speed limitation problem and instability problem might not likely to go away.
So I have decided to give up I2C MCP23017, and divert to SPI MCP23S17

SPI Wiring Plan V0.1

...
by tlfong01
Sat Dec 08, 2018 4:06 am
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

Replacing I2C MCP2307 by SPI MCP23S17[/b] I have been thinking of using Rpi software I2C, but found the speed limitation problem and instability problem might not likely to go away. So I have decided to give up I2C MCP23017, and divert ...
by tlfong01
Fri Dec 07, 2018 2:06 pm
Forum: Automation, sensing and robotics
Topic: Reading old weight scale
Replies: 124
Views: 22053

Re: Reading old weight scale

Replacing I2C MCP2307 by SPI MCP23S17 I have been thinking of using Rpi software I2C, but found the speed limitation problem and instability problem might not likely to go away. So I have decided to give up I2C MCP23017, and divert to SPI ...
by tlfong01
Wed Aug 08, 2018 3:05 pm
Forum: Automation, sensing and robotics
Topic: Relay Module KY-019 5V
Replies: 488
Views: 98095

Re: Relay Module KY-019 5V

(2) But then I can consider forgetting the stupid I2C thing altogether, and switch to SPI based MCP23S17 It's possible to send constant data to the MCP* chip. This will save you some time to change the output faster. But after you send the pulse, you have 75*2uS the time ...

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