main.c

Stand-alone DTM application for UART interface. More...

Macros
#define	UART_TX_PIN   1
#define	UART_RX_PIN   3
#define	BITRATE   UART_BAUDRATE_BAUDRATE_Baud19200
#define	MAX_ITERATIONS_NEEDED_FOR_NEXT_BYTE   21

Enumerations
enum	nrf_gpio_pin_pull_t {   NRF_GPIO_PIN_NOPULL = GPIO_PIN_CNF_PULL_Disabled,   NRF_GPIO_PIN_PULLDOWN = GPIO_PIN_CNF_PULL_Pulldown,   NRF_GPIO_PIN_PULLUP = GPIO_PIN_CNF_PULL_Pullup,   NRF_GPIO_PIN_NOPULL = GPIO_PIN_CNF_PULL_Disabled,   NRF_GPIO_PIN_PULLDOWN = GPIO_PIN_CNF_PULL_Pulldown,   NRF_GPIO_PIN_PULLUP = GPIO_PIN_CNF_PULL_Pullup }
	Enumerator used for selecting the pin to be pulled down or up at the time of pin configuration. More...

Functions
static __INLINE void	nrf_gpio_cfg_output (uint32_t pin_number)
	Function for configuration of pin to use for UART TX. More...
static __INLINE void	nrf_gpio_cfg_input (uint32_t pin_number, nrf_gpio_pin_pull_t pull_config)
	Function for configuration of pin to use for UART RX. More...
static void	uart_init (void)
	Function for UART initialization.
static uint32_t	dtm_cmd_put (uint16_t command)
	Function for splitting UART command bit fields into separate command parameters for the DTM library. More...
int	main (void)
	Function for application main entry. More...

Detailed Description

Macro Definition Documentation

#define UART_TX_PIN   1

Pin used for UART Transmit.

#define UART_RX_PIN   3

Pin used for UART Receive.

#define BITRATE   UART_BAUDRATE_BAUDRATE_Baud19200

Serial bitrate on the UART

#define MAX_ITERATIONS_NEEDED_FOR_NEXT_BYTE   21

Maximum iterations needed in the main loop between stop bit 1st byte and start bit 2nd byte. DTM standard allows 5000us delay between stop bit 1st byte and start bit 2nd byte. As the time is only known when a byte is received, then the time between between stop bit 1st byte and stop bit 2nd byte becomes: 5000us + transmission time of 2nd byte.

Byte transmission time is (Baud rate of 19200): 10bits * 1/19200 = approx. 520 us/byte (8 data bits + start & stop bit).

Loop time on polling UART register for received byte is defined in ble_dtm.c as: UART_POLL_CYCLE = 260 us

The max time between two bytes thus becomes (loop time: 260us / iteration): (5000us + 520us) / 260us / iteration = 21.2 iterations.

This is rounded down to 21.

Note

If UART bit rate is changed, this value should be recalculated as well.

Enumeration Type Documentation

enum nrf_gpio_pin_pull_t

Enumerator
NRF_GPIO_PIN_NOPULL	Pin pullup resistor disabled.
NRF_GPIO_PIN_PULLDOWN	Pin pulldown resistor enabled.
NRF_GPIO_PIN_PULLUP	Pin pullup resistor enabled.
NRF_GPIO_PIN_NOPULL	Pin pullup resistor disabled.
NRF_GPIO_PIN_PULLDOWN	Pin pulldown resistor enabled.
NRF_GPIO_PIN_PULLUP	Pin pullup resistor enabled.

Function Documentation

static __INLINE void nrf_gpio_cfg_output ( uint32_t  pin_number )

static

Parameters

[in]

pin_number

The pin to use as TX.

static __INLINE void nrf_gpio_cfg_input ( uint32_t  pin_number, nrf_gpio_pin_pull_t  pull_config  )

static

Parameters

[in]	pin_number	The pin to use as RX.
[in]	pull_config	Configuration of pull resistor.

static uint32_t dtm_cmd_put ( uint16_t  command )

static

Parameters

[in]

command

The packed UART command.

Returns

result status from dtmlib.

int main

(

void

)

This function serves as an adaptation layer between a 2-wire UART interface and the dtmlib. After initialization, DTM commands submitted through the UART are forwarded to dtmlib and events (i.e. results from the command) is reported back through the UART.