PSoC5LP Lab23: Building a UART‑Based Single‑Application Bootloader

Part A: Bootloader Project (SingleApp_BL)

Procedure

Creating a New Project

1. Launch PSoC Creator.
2. Go to File → Open → Project/Workspace and open your PSoC5LP workspace in the course folder.
3. In the Workspace Explorer, right-click the Workspace and select Add → New Project....
4. Select the correct PSoC 5LP device model number, and use the "Empty Schematic" template.
5. Enter the project name: 23_Bootloader_SingleApp_BL.
6. Click Finish.

Adding PSoC Creator Components

Open TopDesign.cysch and add the following components:

1. UART:
   • Navigate to the Communications catalog in the Component Catalog panel.
   • Find and drag the UART onto the schematic.
2. Bootloader:
   • Navigate to the System catalog.
   • Find and drag Bootloader onto the schematic.
3. Logic '0':
   • Navigate to the Digital → Logic catalog.
   • Find and drag Logic Low '0' onto the schematic.

The TopDesign.cysch will be shown as below:

Configure the Components

1. Configure the UART (UART_1):
   • Double-click UART_1 to open its configuration dialog.
   • Set Name to UART_1.
   • On the Configure tab, set:
     • Mode: Full UART (TX + RX)
     • Baud Rate: 115200
     • Data Bits: 8
     • Parity: None
     • Stop Bits: 1
     • Flow Control: None
   • On the Advanced tab, set:
     • RX Buffer Size: 64
   

   The PSoC 5LP Bootloader component requires a minimum RX buffer size of 64 bytes. Setting a smaller value will cause a build error.

2. Configure the Bootloader (Bootloader_1):
   • Double-click Bootloader_1.
   • Set the following parameters:
     • Name: Bootloader
     • Communication Component: UART
     • Packet Checksum Type: Basic Summation
     • Wait for Command (ms): 5000
     • Enable Fast App Validation: Unchecked
   
3. Configure the Digital Input Pin (Rx_1):
   • Select the Rx_1 component.
   • Rename the component to UART_Rx to indicate its role as the UART receive pin.
4. Configure the Digital Input Pin (Tx_1):
   • Select the Tx_1 component.
   • Rename the component to UART_Tx to indicate its role as the UART transmit pin.

Wiring

Connect the Logic Low '0' output to the reset pin of the UART on the schematic. This holds the UART reset line inactive (deasserted) at all times, ensuring the UART operates normally during bootloader communication.

The new TopDesign.cysch file is shown below:

Pin Assignment

• PSoC 5LP Prototyping Kit Pin Details

Example Firmware C Code

#include "project.h"
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h> 

int main(void)
{
    /* Start the Bootloader.
       Waits up to 5000 ms for a host command via UART.
       If no command is received within the timeout,
       it automatically jumps to the application.
       This function never returns. */
    Bootloader_Start();

    for(;;)
    {
        /* Never reached */
    }
}

Build the project: right-click 23_Bootloader_SingleApp_BL → Set as Active Project → Build → Build "23_Bootloader_SingleApp_BL". Confirm the build succeeds and note the .hex file path in the Build Output window.

Part B: Bootloadable Application Project (SingleApp_App)

Procedure

Creating a New Project

1. Launch PSoC Creator.
2. Go to File → Open → Project/Workspace and open your PSoC5LP workspace in the course folder.
3. In the Workspace Explorer, right-click the Workspace and select Add → New Project....
4. Select the correct PSoC 5LP device model number, and use the "Empty Schematic" template.
5. Enter the project name: 23_Bootloader_SingleApp_App.
6. Click Finish.

Adding PSoC Creator Components

Open TopDesign.cysch and add the following components:

1. Bootloadable:
   • Navigate to the System catalog.
   • Drag Bootloadable onto the schematic.
2. Digital Input Pin (for SW1):
   • Navigate to the Ports and Pins catalog.
   • Drag a Digital Input Pin onto the schematic.
3. Digital Output Pin (for LED1):
   • From the Ports and Pins catalog.
   • Drag a Digital Output Pin onto the schematic.

The TopDesign.cysch is shown below:

Configure the Components

1. Configure the Bootloadable (Bootloadable_1):
   • Double-click Bootloadable_1.
   • Set name to Bootloadable.
   • On the General tab, set:
     • Application version: 0x0000
     • Application ID: 0x0000
     • Application custom ID: 0x00000000
     • Manual application image placement: Unchecked

   • On the Dependencies tab:

     • Bootloader HEX file: Click Browse and navigate to the output folder of 23_Bootloader_SingleApp_BL, select 23_Bootloader_SingleApp_BL.hex.
     • Bootloader ELF file: Click Browse and navigate to the same output folder, select 23_Bootloader_SingleApp_BL.elf.
   
   

   The Bootloader project (23_Bootloader_SingleApp_BL) must be built before the HEX and ELF files are available for browsing.

2. Configure the Digital Input Pin (Pin_1):
   • Double-click Pin_1.
   • Set the following:
     • Name: nSW1
     • Type: Digital Input
     • HW Connection: unchecked
     • Drive Mode: Resistive Pull Up
     • Initial Drive State: High (1)
   
3. Configure the Digital Output Pin (Pin_2):
   • Double-click Pin_2.
   • Set the following:
     • Name: LED1
     • Type: Digital Output
     • HW Connection: Unchecked
     • Drive Mode: Strong Drive
     • Initial State:Low (0)
   

Pin Assignment

• PSoC 5LP Prototyping Kit Pin Details

Example Firmware C Code

#include "project.h"
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h> 

int main(void)
{
    CyGlobalIntEnable; // Enable global interrupts

    for(;;) {
        // nSW1 is active-low:
        //   nSW1_Read() == 0 → button pressed
        //   nSW1_Read() == 1 → button released
        if (nSW1_Read() == 0) {
            LED1_Write(1); // Button pressed  → LED ON
        } else {
            LED1_Write(0); // Button released → LED OFF
        }
        CyDelay(20);    
    }
}

Build the project: right-click 23_Bootloader_SingleApp_App → Set as Active Project → Build → Build "23_Bootloader_SingleApp_App". Confirm the build succeeds and note the .cyacd file path in the Build Output window.

Part C: Programming and Testing

Step 1 — Program the Bootloader via KitProg

1. Connect the CY8CKIT-059 to the PC using the KitProg USB connector (the left-side USB port labeled KitProg).
2. In PSoC Creator, right-click Exp1_BL → Program.
3. Wait for programming to complete. The device now runs the Bootloader and immediately begins the 5-second wait window.

Step 2 — Transfer the Application via Bootloader Host

1. Press the Reset button on the CY8CKIT-059. The Bootloader starts and opens its 5-second UART command window.
2. Open PSoC Bootloader Host: in PSoC Creator, go to Tools → Bootloader Host.
3. Configure the tool:

   Field	Value
   File	Browse to 23_Bootloader_SingleApp_App.cyacd.cyacd
   Protocol	UART
   COM Port	CY8CKIT-059 UART COM port (check Windows Device Manager → Ports)
   Baud Rate	115200 bps

4. Click the Program within the 5-second timeout window.
   Wait for the transfer to complete. The device resets automatically and launches Exp1_App.

Step 3 — Verify Operation

ActionExpected ResultPress and hold SW1LED1 turns ONRelease SW1LED1 turns OFFPress Reset buttonLED goes OFF; 5-second pause (Bootloader waiting); LED behavior resumes