Lab: GPIO and Peripherals on Real Hardware

Course 1 · Module 3 Type: Hands-on lab (block-by-block, then short integration) Suggested time: 2.5–3 hours

Read first: Lesson · API map · ← Table of Contents · ← M02 · M04 →

Note: the snippets in this lab use the API of the TESAIoT Bitstream firmware, which is not yet open source. See detail and equivalent examples in the public SDK in the note at the top of the lesson GPIO and Peripherals through a Driver API

Useful references during the lab

Document	Use when
TESAIoT Developer Hub	GPIO / Sensors / Embedded examples
Snippets in the Lesson	The TESA Firmware SDK’s real function names
TESAIoT_Hackathon	HEX / Flasher, if using the ready-made pack
Bitstream Studio	Watching telemetry (extra)

Lab Goals

Control an LED with led_controller_* (or Cy_GPIO_*)
Receive button events with cm55_button_*
Send a UART log (printf / LOG_INFO / cm55_uart_send)
Get at least one of: PWM (bitstream_led_pwm_*) · ADC (cm55_adc_*) · I²C (sensor_sht40_*, or another sensor on your board) working
Fill in the real API names in peripheral-api-map.md

Prerequisites

Have met the M02 bar
An example project already linked to the TESA Firmware SDK
A USB cable + a serial terminal
Know the kit in hand (AI vs Eval — affects the second button and the POT)

Lab A — GPIO: LED + Button (required)

Call led_controller_init (if the project hasn’t already) and try led_controller_set / led_controller_toggle
Call cm55_button_init, then bind cm55_button_on_pressed(BUTTON_ID_0, …) to toggle the LED
Flash it and demonstrate it on the board

Pass when: pressing the button reliably changes the LED’s state

/* A short approach — see detail in Lesson §2 */
(void)led_controller_init();
(void)cm55_button_init();
(void)cm55_button_on_pressed(BUTTON_ID_0, on_btn_pressed);

Lab B — UART log (required)

In the button callback (or a loop), print a message, such as btn toggled
Open a terminal on the KitProg3 port at the project’s baud rate
Confirm the message matches the button event

printf("btn toggled\r\n");
/* or */ LOG_INFO("LAB", "btn toggled");

Pass when: you see the message matching the button event

Lab C — Choose at least one (required)

C1 PWM

(void)bitstream_led_pwm_init();
(void)bitstream_led_pwm_set_brightness(0, 20);
(void)bitstream_led_pwm_set_brightness(0, 80);

Pass when: you can clearly see at least 2 different brightness levels

C2 ADC (Eval kit with POT)

(void)cm55_adc_init();
int16_t mv = cm55_adc_read_pot_mv();
printf("POT mV=%d\r\n", (int)mv);

Pass when: the value changes when you turn the POT, and can be printed over UART

C3 I²C sensor

(void)sensor_sht40_startup();
sht40_sample_t s;
if (sensor_sht40_read(&s)) {
    printf("T=%.2f RH=%.2f\r\n", (double)s.temperature, (double)s.humidity);
}

(or another sensor on your board — sensor_bmi270_*, etc.)

Pass when: you can read a value and print it over UART

Lab D — Mini integration (recommended)

Combine A+B with the result from C, for example ADC → PWM duty, or a button → switching a mode + a UART log

Delay inside a task:

vTaskDelay(pdMS_TO_TICKS(50));

Optional: open Bitstream Studio if the firmware sends telemetry

Short report (5–10 lines)

The BSP / board name
A table of tasks → the real API name (from the API map)
The results of Lab A/B/C

Troubleshooting

Symptom	How to fix it
The LED doesn’t light	The wrong `led_id_t` · the active level · the BSP not yet initialised
The button gives no event	Haven’t called `cm55_button_init` / bound the callback · used the wrong `BUTTON_ID_*`
UART is silent	The COM port / baud rate · retarget not ready yet · `cm55_uart_out_*` still locked
I²C fails	The sensor isn’t ready · forgot to lock the bus when writing a low-level driver · the wrong address
ADC always reads 0	The kit has no POT · haven’t called `cm55_adc_init`
PWM doesn’t change	Haven’t called `bitstream_led_pwm_init` · `led_id` out of range

Submit checklist

Lesson · API map · Table of Contents · M04 →

Cite this lesson

If you teach from this lesson or reuse it in slides or documents, credit it with the text below. If you changed it, add (adapted) after the title.

"Lab: GPIO and Peripherals on Real Hardware" from TESA Open Knowledge by the Thai Embedded Systems Association (TESA), https://github.com/tesaiot/tesa-qualification-program, licensed under CC BY-NC 4.0

Thai attribution: "แล็บ: GPIO และอุปกรณ์ต่อพ่วงบนฮาร์ดแวร์จริง" จาก TESA Open Knowledge โดยสมาคมสมองกลฝังตัวไทย (Thai Embedded Systems Association: TESA) https://github.com/tesaiot/tesa-qualification-program สัญญาอนุญาต CC BY-NC 4.0

Lesson link: https://tesaiot.github.io/tesa-qualification-program/en/courses/firmware-sdk-edge-ai/m03-gpio-peripherals/l02-lab/

This lesson adapts the source below; keep its credit too.
https://github.com/drsanti/TESAIoT-Courses/blob/287c21814ba8c75f693136616dcd270349a15966/C1/M03/lab.md · Original content by Asst. Prof. Dr. Santi Nuratch (ผศ.ดร.สันติ นุราช), KMUTT. Course 1 (C1/) of drsanti/TESAIoT-Courses. TESA funded the work and holds the rights; published here under CC BY-NC 4.0. The upstream repository carries no licence file. Text kept faithful; structure, front matter, quizzes and notes added by TESA Open Knowledge.

Full guide: how to cite TESA

Content is licensed CC BY-NC 4.0. Reuse it non-commercially and credit the Thai Embedded Systems Association (TESA) every time. · How to cite TESA