Unable to Change SPI SCLK in SPI.cpp when using different IDEs (Component vs. PlatformIO)#708
Description
Hardware:
Board: ESP32 DevKit-C
Core Installation/update date: Latest
IDE name: Multiple (ESP-IDF Arduino Component vs. Platform IO)
Flash Frequency: 40Mhz
Upload Speed: 115200
Summary:
I've come across an interesting roadblock. I am not able to change the SPI SLCK frequency in the SPI.cpp library when using arduino-esp32 as a ESP-IDF component. When I use PlatformIO with identical settings, I am able to change the SPI SLKC frequency. It has nothing to do with the U8g2 library as I have tried to hardcode the SPI.cpp frequency values without success.
Description
Arduino-esp32 dictates 4 ways of using the Arduino API with ESP-IDF in the instructions/readme.
Method 1 - Using Arduino API as ESP-IDF Component [This doesn't work]
One of those ways is to use Arduino API as an ESP-IDF component as described here. I managed to add Arduino API to ESP-IDF using this method. Next, I've added a component.mk file to @olikraus's U8g2_Arduino fork.
Component.mk has the following options to add source directors and include files:
COMPONENT_SRCDIRS:=src src/clib COMPONENT_ADD_INCLUDEDIRS:=src src/clib Now, U8g2 is a component of ESP-IDF.
Everything works except There is one problem. Usually, I am able to edit the SPI frequency in the u8x2_d_ssd1306_128x64_noname.c,
/* sck_clock_hz = */ 10000000UL,
however, no matter what frequency I set and upload to ESP32, I always get 8MHz as the clock freq. I've validated it using a scope.
I've hardcoded the SPI freq to 10 MHz in the arduino-esp32 SPI.c file and it still doesn't work:
void SPIClass::beginTransaction(SPISettings settings){//check if last freq changed uint32_t cdiv = spiGetClockDiv(_spi); if(_freq != settings._clock || _div != cdiv){// _freq = settings._clock; _freq = 10000000UL; // Temporarily hardcoding it for debug purpose. No matter what freq I set here, the default is always 8 MHz. _div = spiFrequencyToClockDiv(_freq)} spiTransaction(_spi, _div, settings._dataMode, settings._bitOrder); _inTransaction = true} So I tried to use arduino-esp32 using PlatformIO. This problem does not happen when I use Platform IO and downloading latest U8g2 library + arduino-esp32 platform.
Method 2 - Using PlatformIO [This works]
So, I tried the same test as above and I changed the u8x8_d_ssd1306_128x64_noname.c LINE 235 to use 10 MHz as the clock frequency.
/* sck_clock_hz = */ 10000000UL,
This time, using Platform IO toolchain, it works! I checked it with a scope and I am getting 10 MHz as the clock frequency.
Scope screenshot says 9.62 MHz but it is 10 MHz when I change the horizontal scale.
I am pretty sure I am missing something obvious here.
Any ideas on what must be going on?
Sketch:
#include<Arduino.h> #include<U8g2lib.h> #include<SPI.h> #include<Wire.h> U8G2_SSD1306_128X64_NONAME_F_4W_HW_SPI display1(U8G2_R0, /* CS = */16, /* DC = */17, /* RS = */4); voidsetup(void){display1.begin(); display1.setFont(SPINZERO); // Font file not shown here display1.setFontPosCenter()} voidloop(void){staticunsignedlong thisMicros = 0; staticunsignedlong lastMicros = 0; for (int i = 0; i < 60; i++){display1.clearBuffer(); display1.setCursor(64,20); display1.print("FPS TEST!"); // tpf = Time Per Frameunsignedlong tpf = thisMicros - lastMicros; display1.setCursor(64,32); display1.print(tpf); display1.setCursor(88,32); display1.print("yS/F"); // fps = Frame Per Secondunsignedlong fps; if (tpf ==0){fps = 0} else{fps = 1000000/tpf} display1.setCursor(64,44); display1.print(fps); display1.setCursor(88,44); display1.print("FPS"); display1.sendBuffer(); lastMicros = thisMicros; thisMicros = micros()} }