I have a small nRF51822 module that I want to use for UART communication without handshaking, and I'm having problems with reliability. Basically the nRF51822 crashes and reboots if I send a burst of data into its UART.
I've reverted to the ble_peripheral/ble_app_uart example from SDK 9.0.0, and the ONLY change I've made is to change APP_UART_FLOW_CONTROL_ENABLED to APP_UART_FLOW_CONTROL_DISABLED in the uart_init() function. My nRF51822 is wired as per the P10028 board (i.e. the UART TXD and RXD signals are connected to pins P09 and P11).
My nRF51822 module runs and I can connect to it from my phone, and using a PC with terminal emulator I can send individual characters through it to my phone without any problems. However, when I try to transmit a burst of data (by sending a small file from the terminal emulator) the nRF51 crashes and reboots even though the size of the data is well below the default UART_RX_BUF_SIZE value of 256.
I've tried both S110 SD 8.0.0 and S130 1.0.0. The software seems to cope with 50-100 bytes of data but crashes with a 200 byte burst.
Can the nRF51 work reliably without UART handshaking? Is there something else I need to do in the software to ensure reliable operation?
Thanks.
UPDATE: I've just found that the same problem occurs with handshaking enabled, and also happens with my nRF51 DK board. Can someone at Nordic please try the following:
- Program a nRF51 DK board as a peripheral using S110 or S130 and the standard ble_app_uart example.
- Establish a connection to the nRF51 DK board from a Central BLE device.
- Using a PC and a terminal emulator (I'm using TeraTerm), transmit a 200-byte file to the nRF51 DK board's COM port.
- The nRF51 crashes and reboots immediately.
However, I found if I modify TeraTerm to add a 1ms delay between characters then all the data is handled without problem.
It appears that the nRF51 cannot cope with a rapid burst of incoming UART data, regardless of whether handshaking is enabled or not.
