C SDK Integration

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C SDK Only

The functions and information on this page are available only for the C SDK .

The C SDK includes working implementations for:

• Linux
• Windows
• STM32 microcontrollers

If your platform differs, use these implementations as a reference to adapt the SDK accordingly. See the sections below to learn how to integrate the C SDK.

Prerequisites

Before running the C SDK, you need to configure the following:

1. Implement a method for reading and writing bytes from the platform's serial port connected to the VPOS. The SDK interacts with the hardware through a serial interface, and the following functions must be implemented:
   • drv_usart_rx_byte(): Reads a single byte from the serial port.
   • drv_usart_rx_chunk(): Reads multiple bytes in one operation.
   • drv_usart_get_rx_pending(): Returns the number of pending bytes in the serial buffer.
   • drv_usart_tx_data(): Sends data bytes to the VPOS device.
2. A periodic timer tick should be implemented to invoke the function vmc_link_background() with an interval of 5 ms to 10 ms. Additionally, the function cpu_platform_get_time() should return a continuously incrementing millisecond counter since the system startup.

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Verify Communication

Before proceeding to vending operations, ensure that UART communication with VPOS is functional:

• Check for data transmission and reception.
• Validate that event callbacks are triggered correctly.

Integration Steps

To get started with the C SDK, follow the steps below.

you can refer to the provided mymain.c file a sample code and import the necessary namespaces in your code.

1. Instantiate a VMC configuration object:

   C

   vmc_config_t   	config;
   

2. Fill in the appropriate fields. The following code block presents a standard configuration:

   C

   vmc_init()
   	__strcpy(config.model, "marshall-c-sdk-demo");
   	__strcpy(config.serial, "01234567");
   	__strcpy(config.sw_ver, "vmc app version");
   	__strcpy(config.vmc_hw_ver, “01234567”);
   	__strcpy(config. vmc_manuf_code, “manuf”);
   
   	config.multi_vend_support = __false;
   	config.multi_session_support = __false;
   	config.price_not_final_support = __false;
   	config.reader_always_on = __false;
   	config.always_idle = __false;
   	config.explicit_vend_success = __false;
   	config.vend_denied_policy = vend_denied_policy_persist_e;
   
   	config.mifare_approved_by_vmc_support = __false;
   	config.mag_card_approved_by_vmc_support = __false;
   	config.qr_approved_by_vmc_support  = __false;
   
   	config.dump_packets_level = debug_level_dump_none;
   	config.debug = __true;
   
   

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   Mandatory Fields

   The customer machine information are mandatory fields for the VMC configuration, these are the model, serial , hw_ver and the manuf_code. Read more about these fields in VMC Configuration Object.

3. Configure the SDK and register to link events.

   C

   vmc_link_register_callback((vmc_link_event_handler_cb_t)vmc_link_event_handler_cb);
   vmc_vend_register_callback((vmc_vend_event_handler_cb_t)vmc_vend_event_handler_cb);
   

4. Start the SDK and wait for the onReady() event:

   C

   vmc_link_start()
   

Implementing Payment Flows

As explained in Payment Flows, the Marshall SDK supports various payment flows. The pages below explain how to implement each in your VMC using the C SDK.