nRF52832 Enabling UART easyDMA results in global variables being assigned random values

[lzq597]

IDE：SES for ARM V5.42a

SDK：nRF5_SDK_16.0.0

I am develop BLE device with nRF52832. I found that some global variables were assigned ramdom values if I enable UART easyDMA. If UART easyDMA is disabled, this bug will not occur.These global variables should be zero. Because I have already initialised them to zero.

The address of m_rx_fifo in app_uart_fifo.c is 0x20004688, The address of m_rx_fifo in app_uart_fifo.c is 0x20004698.

The address of global variables assigned random values is 0x20005660.

m_rx_fifo address = 0x20004688
m_tx_fifo address = 0x20004698

ble_sleep_count = 143, addr = 0x20005660

msg_type:255, addr = 0x20005661

data_get[0] = 96, addr = 0x20005664

[Susheel Nuguru]

+1 to what Jörg Fischer said. 

The address of global variables assigned random values is 0x20005660.

These are not randomly assigned but how the compiler works, if you want to have a predictable memory management on it then use a heap or similar and have some checks in your code that boundaries on that memory are not being broken.