EC-9.4 Analog In and Analog Out on the Chip
You can configure an on-chip converter for a real sensor, work out whether the source impedance is low enough, tell the resolution on the datasheet from the accuracy you will actually get, and produce an analog output with or without a converter.
Before:S5-2. Computer Architecture and MicroprocessorsEC-7. Signals and SystemsUnlocks:PE1-4. Embedded C ProgrammingEC-13. Laboratory Practice, in Sequence
The converter inside a microcontroller is the point where the physical world becomes a number, and its datasheet numbers are the most over-trusted in embedded work. Twelve bits of resolution on the front page rarely means twelve bits of usable accuracy on a board, and knowing why is the difference between a reading and a guess.
Work through these
The on-chip converter, and the reference it measures against
A converter reports the input as a fraction of its reference, so the reference is the measurement standard. A reference taken from a noisy supply makes every reading move with the supply.
NPTEL: Introduction to Embedded System Design (NSUT and IIT Jammu) · CourseSample and hold, acquisition time and source impedance
The converter charges a small internal capacitor from your signal before converting. A high source impedance cannot charge it in the allowed time, and the reading comes back low with no error reported.
NPTEL: Embedded Systems Design (IIT Kharagpur) · CourseResolution against accuracy on a real part
Resolution is how finely the range is divided; accuracy is how close the answer is to the truth. Offset, gain error and non-linearity in the datasheet usually cost several of the bits the headline number promised.
NPTEL: Introduction to Embedded System Design (NSUT and IIT Jammu) · CourseStarting a conversion three ways
A conversion can be started by software, by a timer, or by direct memory access that also stores the result. The last two are what let you sample at an exact rate without the processor being involved.
NPTEL: Embedded System Design with ARM (IIT Kharagpur) · CourseGetting an analog output without a converter
Many parts have no digital-to-analog converter at all. A pulse of varying width through a low-pass filter gives an average voltage, which is enough for a motor, a lamp or an audio tone.
NPTEL: Microcontrollers and Applications (IIT Kanpur) · CourseGrounding an analog input on a digital chip
Switching digital outputs put current through the same ground the converter measures against. Separate analog ground and supply pins exist for that reason, and using them is what makes the last two bits mean anything.
NPTEL: Embedded Systems Design (IIT Kharagpur) · Course
Sign in to keep your progress.
Free resources
We haven't checked most of these for screen reader use yet.
- FreeNPTEL / IIT Kharagpur · CourseNPTEL: Embedded Systems Design (IIT Kharagpur)
- FreeNPTEL / Netaji Subhas University of Technology and IIT Jammu · CourseNPTEL: Introduction to Embedded System Design (NSUT and IIT Jammu)
- FreeNPTEL / IIT Kharagpur · CourseNPTEL: Embedded System Design with ARM (IIT Kharagpur)
- FreeNPTEL / IIT Kanpur · CourseNPTEL: Microcontrollers and Applications (IIT Kanpur)
Links last checked 3 Sept 2026.
Stuck here?
Ask a mentor. A real person answers, and they can see exactly which topic you're on. Usually within a couple of working days.
Checking your session…
Topics shown in module order.