Read the value of a register in arduino

Question

I want to read the value of the register (8-bit). In particular I want to read the values of:

1. The Timer/Counter - TCNT0 ( Adress 0x26 (0x46) )
2. The output compare registers - OCR0A and OCR0B.

Is there a way to read them with the Arduino program?

• chrisl: How about just using them in your program? You can use the register names directly
• Ugo Mela: @chrisl So is the output of Serial.print(TCNT0, BIN) the current value (in binary) of the register?
• chrisl: Yes, that should work. You see much code on the web, where timers are configured by directly writing to the registers. You can try it. Write a value to a register and read it back. Though, if you are using the Arduino core, the timer0 counter will change, because it is used for millis() and siblings. You can try it with a currently disabled timer.

Answer 1

To convert my comments to an answer:

You can use the register names directly. They are defined in the boards/chips core. To read them, simply use the names in your calculations. Write to the registers by setting the value of the registers name (like a variable: TCNT0 = 0;). Be sure to look into the datasheet, to check the behavior of that register.

• jose can u c: As noted, do check the datasheet -- some register flags are cleared (zeroed) by writing a 1 to them.