Hello
I am trying to figure out the ram retention on my nRF52-DK using SES and SDK v17.1.0. I've run through the example ram_retention, and studied a topic in Nordic's documentation, as well as a couple of threads here in DevZone, like this one, and this one. I adapted my code to implement RAM retention using the given examples, but it didn't work for me.
I did all the mentioned steps:
- declared the variable I want to retain in the .non_init section (
static uint32_t ble_activate __attribute__((section(".non_init"))); ) - turned the RAM powered on during the SystemOFF sleepmode:
// Configure the RAM retention parameters uint8_t i; for(i = 0; i < 8; i++) // Retain RAM 0 - RAM 7 { sd_power_ram_power_set(i, (POWER_RAM_POWER_S0POWER_On << POWER_RAM_POWER_S0POWER_Pos) | (POWER_RAM_POWER_S1POWER_On << POWER_RAM_POWER_S1POWER_Pos) | (POWER_RAM_POWER_S0RETENTION_On << POWER_RAM_POWER_S0RETENTION_Pos) | (POWER_RAM_POWER_S1RETENTION_On << POWER_RAM_POWER_S1RETENTION_Pos)); } // Delay for one second nrf_delay_ms(1000); - And checking up the NRF_POWER->GPREGRET for a pre-set value upon every wakeup.
However, I see that value is not preserved since I am outputting it using printf and it returns back as a nonsense number. Please, find my main.c attached. The crucial steps are implemented in void mers_ram_retention(void). The code is loosely based on ble_app_uart example, that is, in configures BLE stack as per original method and then starts advertising, and finally, goes to SystemOFF.
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#include <stdint.h>
#include <string.h>
#include "app_timer.h"
#include "bsp_btn_ble.h"
#include "nrf_pwr_mgmt.h"
#if defined (UART_PRESENT)
#include "nrf_uart.h"
#endif
#if defined (UARTE_PRESENT)
#include "nrf_uarte.h"
#endif
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
#include "nrf_delay.h"
#include "MERS_BLE.h"
#include "MERS_LoRaWAN.h"
#include "MERS_fstorage.h"
/* Project global variables */
extern uint8_t key_cnt;
extern bool keys_received;
extern bool ble_connected;
static uint32_t ble_activate __attribute__((section(".non_init")));
/**@brief Function for initializing the timer module.
*/
static void timers_init(void){
ret_code_t err_code = app_timer_init();
APP_ERROR_CHECK(err_code);
}
/**@brief Function for handling events from the BSP module.
*
* @param[in] event Event generated by button press.
*/
void bsp_event_handler(bsp_event_t event){
uint32_t err_code;
switch (event)
{
case BSP_EVENT_SLEEP:
sleep_mode_enter();
break;
case BSP_EVENT_DISCONNECT:
//err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
//if (err_code != NRF_ERROR_INVALID_STATE)
//{
// APP_ERROR_CHECK(err_code);
//}
break;
case BSP_EVENT_WHITELIST_OFF:
//if (m_conn_handle == BLE_CONN_HANDLE_INVALID)
//{
// err_code = ble_advertising_restart_without_whitelist(&m_advertising);
// if (err_code != NRF_ERROR_INVALID_STATE)
// {
// APP_ERROR_CHECK(err_code);
// }
//}
break;
default:
break;
}
}
/**@brief Function for handling app_uart events.
*
* @details This function will receive a single character from the app_uart module and append it to
* a string. The string will be be sent over BLE when the last character received was a
* 'new line' '\n' (hex 0x0A) or if the string has reached the maximum data length.
*/
/**@snippet [Handling the data received over UART] */
void uart_event_handle(app_uart_evt_t * p_event){
static uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
static uint8_t index = 0;
uint32_t err_code;
switch (p_event->evt_type)
{
case APP_UART_DATA_READY:
UNUSED_VARIABLE(app_uart_get(&data_array[index]));
index++;
//if ((data_array[index - 1] == '\n') ||
// (data_array[index - 1] == '\r') ||
// (index >= m_ble_nus_max_data_len))
//{
// if (index > 1)
// {
// NRF_LOG_DEBUG("Ready to send data over BLE NUS");
// NRF_LOG_HEXDUMP_DEBUG(data_array, index);
// do
// {
// uint16_t length = (uint16_t)index;
// err_code = ble_nus_data_send(&m_nus, data_array, &length, m_conn_handle);
// if ((err_code != NRF_ERROR_INVALID_STATE) &&
// (err_code != NRF_ERROR_RESOURCES) &&
// (err_code != NRF_ERROR_NOT_FOUND))
// {
// APP_ERROR_CHECK(err_code);
// }
// } while (err_code == NRF_ERROR_RESOURCES);
// }
// index = 0;
//}
break;
case APP_UART_COMMUNICATION_ERROR:
APP_ERROR_HANDLER(p_event->data.error_communication);
break;
case APP_UART_FIFO_ERROR:
APP_ERROR_HANDLER(p_event->data.error_code);
break;
default:
break;
}
}
/**@snippet [Handling the data received over UART] */
/**@brief Function for initializing the UART module.
*/
/**@snippet [UART Initialization] */
static void uart_init(void){
uint32_t err_code;
app_uart_comm_params_t const comm_params =
{
.rx_pin_no = RX_PIN_NUMBER,
.tx_pin_no = TX_PIN_NUMBER,
.rts_pin_no = 0,
.cts_pin_no = 0,
.flow_control = APP_UART_FLOW_CONTROL_DISABLED,
.use_parity = false,
#if defined (UART_PRESENT)
.baud_rate = NRF_UART_BAUDRATE_115200
#else
.baud_rate = NRF_UARTE_BAUDRATE_115200
#endif
};
APP_UART_FIFO_INIT(&comm_params,
UART_RX_BUF_SIZE,
UART_TX_BUF_SIZE,
uart_event_handle,
APP_IRQ_PRIORITY_LOWEST,
err_code);
APP_ERROR_CHECK(err_code);
}
/**@snippet [UART Initialization] */
/**@brief Function for initializing buttons and leds.
*
* @param[out] p_erase_bonds Will be true if the clear bonding button was pressed to wake the application up.
*/
static void buttons_leds_init(bool * p_erase_bonds){
bsp_event_t startup_event;
uint32_t err_code = bsp_init(BSP_INIT_LEDS | BSP_INIT_BUTTONS, bsp_event_handler);
APP_ERROR_CHECK(err_code);
err_code = bsp_btn_ble_init(NULL, &startup_event);
APP_ERROR_CHECK(err_code);
*p_erase_bonds = (startup_event == BSP_EVENT_CLEAR_BONDING_DATA);
}
/**@brief Function for initializing the nrf log module.
*/
static void log_init(void){
ret_code_t err_code = NRF_LOG_INIT(NULL);
APP_ERROR_CHECK(err_code);
NRF_LOG_DEFAULT_BACKENDS_INIT();
}
/**@brief Function for initializing power management.
*/
static void power_management_init(void){
ret_code_t err_code;
err_code = nrf_pwr_mgmt_init();
APP_ERROR_CHECK(err_code);
}
/**@brief Function for handling the idle state (main loop).
*
* @details If there is no pending log operation, then sleep until next the next event occurs.
*/
static void idle_state_handle(void){
if (NRF_LOG_PROCESS() == false)
{
nrf_pwr_mgmt_run();
}
}
/**@brief A function to fetch LoRaWAN keys
*/
mers_ble_keys_t mers_ble_obtain_keys(void){
/* Check if the LoRa keys have been received and store them in the Flash */
if (keys_received){
NRF_LOG_INFO("Received 4 keys.");
NRF_LOG_FLUSH();
mers_store_lora_keys();
ble_activate = false;
/* Keys are received, we can disconnect and disable BLE */
//mers_ble_disconnect(); // <--- Leave the disconnect decision to the Smartphone
ble_connected = false;
return MERS_KEYS_RECEIVED_OK;
}
else
return MERS_KEYS_RECEIVED_NOT_OK;
}
void mers_ram_retention(void){
// Check if chip is waking up after a SoftReset.
if(NRF_POWER->GPREGRET == 0xBB){
printf("\n\rble_activate value: %d", ble_activate);
// Reset GPREGRET register
// NRF_POWER->GPREGRET = 0x00;
}
else {
ble_activate = 0x01UL;
// Store magic number in GPREGRET register to indicate that the content should be checked upon reset.
NRF_POWER->GPREGRET = 0xBB;
}
// Configure the RAM retention parameters
uint8_t i;
for(i = 0; i < 8; i++) // Retain RAM 0 - RAM 7
{
sd_power_ram_power_set(i, (POWER_RAM_POWER_S0POWER_On << POWER_RAM_POWER_S0POWER_Pos) |
(POWER_RAM_POWER_S1POWER_On << POWER_RAM_POWER_S1POWER_Pos) |
(POWER_RAM_POWER_S0RETENTION_On << POWER_RAM_POWER_S0RETENTION_Pos) |
(POWER_RAM_POWER_S1RETENTION_On << POWER_RAM_POWER_S1RETENTION_Pos));
}
// Delay for one second
nrf_delay_ms(1000);
}
/**@brief Application main function.
*/
int main(void){
bool erase_bonds;
// Initialize.
uart_init();
log_init();
timers_init();
buttons_leds_init(&erase_bonds);
power_management_init();
fstorage_init();
// Start execution.
printf("\n\r*********************************");
printf("\n\r MarineEye Remote Sensor" );
printf("\n\r Pero, 2022" );
printf("\n\r*********************************");
/*
Add Git version printout
*/
NRF_LOG_INFO("Debug logging for MERS over RTT started.");
NRF_LOG_FLUSH();
mers_ram_retention();
printf("\n\rble_activate value: %d", ble_activate);
printf("\n\rkeys_received value: %d", keys_received);
/* Activate the BLE radio and start advertising */
if (ble_activate){
mers_ble_init();
printf("\n\rBLE Advertising started.\n\r");
}
else{
printf("\n\rBLE not activated.");
}
///* Check for the keys in the Flash */
//if (mers_read_lora_keys() != LORA_KEYS_IN_FLASH_OK){
// ble_activate = true;
// /* Activate BLE radio and get the keys */
// mers_ble_obtain_keys();
//}
//else{
// NRF_LOG_INFO("\n\rLoRaWAN Keys found.\n\rBLE radio not started.");
// /*
// Do the job with Lora keys
// */
//}
//NRF_LOG_INFO("\n\rDevice going to sleep");
//NRF_LOG_FLUSH();
uint32_t dummy_cntr = 0;
while(1){
if (ble_connected){
if(mers_ble_obtain_keys() == MERS_KEYS_RECEIVED_OK){
printf("\n\rLoRaWAN Keys received.");
sleep_mode_enter();
}
ble_activate = 0UL;
}
else{
dummy_cntr++;
if ((dummy_cntr % 40) == 0)
printf("\n\rble_activate value: %d", ble_activate);
}
idle_state_handle();
}
}
/**
* @}
*/
Could you please tell me what went wrong?
Best,
W
