I'm trying to move data over the uart characteristic. I followed the guidelines here devzone.nordicsemi.com/.../
In the main loop I am calling sd_ble_gatts_hvx until it returns buffers full, careful not to increment the buffer pointer until after it returns NRF_SUCCESS.
I am seeing that groups of 2-3 later packets are copied over some preceding packets. This causes some packets to be duplicated and some packets to be dropped. I tried making hvx_params into a static array so each time sd_ble_gatts_hvx gets a different copy that won't be overwritten or go out of scope. There isn't any other ble transmission outside of moving this data in the main loop.
The only way I can get this to work is to send 1 packet, wait for BLE_EVT_TX_COMPLETE, and then send the next packet. This way is unusable at 300 bytes per second. Getting 4kb/s doing it the other way with dup/dropped packets.
Heres my code, trying to send 51 packets, BLE_EVT_TX_COMPLETE event clears ble_busy and the char* pointer is to flash data that isn't changing or going out of scope. How could I be getting duplicate/dropped packets? I edited out other error handling in this code, I have not seen any kind of error except for buffers-full error.
void ble_send_buffer(char* buf)
{
uint32_t err_code;
char* bp = buf;
uint16_t nsent = 0;
while(nsent < 51)
{
ble_busy = 1;
while(1)
{
err_code = ble_nus_string_send(&m_nus, (uint8_t*)bp, 20);
if (err_code == BLE_ERROR_NO_TX_BUFFERS )
{
break;
} else if(err_code == NRF_SUCCESS)
{
nsent++;
bp += 20;
if(nsent == 51) break;
}
}
while(ble_busy); //wait for tx complete after breaking
}
}
