8051 timers — counting resources How many 16-bit counter/timer modules are provided in a standard 8051 microcontroller?

Introduction / Context:
The classic 8051 architecture includes hardware timers used for time delays, event counting, and baud-rate generation. Recognizing how many and what width these timers are is a fundamental specification question.

Given Data / Assumptions:

• Baseline 8051 (not extended variants).
• Each timer is 16-bit wide in the most common modes.
• Naming convention: Timer 0 and Timer 1.

Concept / Approach:
Standard 8051 devices implement two 16-bit timer/counter modules: Timer 0 and Timer 1. These support multiple modes (including 13-bit, 16-bit, and auto-reload modes), and can be driven by internal clocks or external pins T0 and T1 (P3.4, P3.5).

Step-by-Step Solution:

Verification / Alternative check:
Any 8051 datasheet block diagram clearly shows two timer/counter modules labeled Timer 0 and Timer 1.

Why Other Options Are Wrong:

• 1, 3, or 4: do not match the standard 8051 core (some derivatives add Timer 2, but that is not the classic 8051).

Common Pitfalls:
Confusing classic 8051 with later derivatives that include Timer 2; always read the exact variant's datasheet.

Final Answer:
2