adcesp8266sensorspi
I'm trying to connect an MCP3008 to an ESP07 through the SPI interface. (A bidirectional level 5V – 3.3V is used in between but it doesn't matter)
However this is not working because:
The CS pin is the pin 15 of ESP07 which needs to be GND otherwise it doesn't boot.
The MCP3008 CS is on HIGH.
I'm trying to connect several analogue sensors to the ESP. Is there an workaround? What is to be done? Am I missing something?
223 touch has an option to set between active high or active low mode so you can skip transistor.
You must add a resistor between the GPIO output and the transistor’s base. If the transistor’s base was driven at 3.3V, it would drain a few amperes and either the transistor or the MCU would blow. If it did not blow, it probably means that something is limiting the current on the GPIO output, but I would not recommend depending on this.
If your MCU needs it, you certainly can add a pull-up resistor to GPIO2. As long as its value is high enough (10k is standard for me), the MCU can easily drive the pin low when requested so.
The schematic would be something like this:
simulate this circuit – Schematic created using CircuitLab
Edit: R2 should be much lower than R1, but still high, so I fixed the values and replaces the single transistor with a darlington-like structure to have a high-enough gain to properly drive the relay.
Best Answer
This statement does not make sense. CS pin of MCP3008 is an input. It cannot be "on HIGH". It can only be at whatever level you connect it to.
The GPIO15 works as HSPI_CS pin only in HSPI mode, i.e. with ESP8266 as slave.
In your schematics ESP8266 is a master. You can use pretty much any pin to control MCP3008 CS. Normally GPIO0 is used for this.
UPDATE
If your board has external flash chip then SPI is used for that. In this case you can try using HSPI interface. Connect GPIO15 to GND with 10k pull-down resistor. This will ensure correct boot. After boot you can initialize and use HSPI in master mode.