In our device, we use BLUENRGGCSP module (marking on the chip: BLUENRG AZ 001 P6 TW 4 18) in WLCSP34 package. We also have BlueNRG Eval Kit. In our device and in the Evaluation board, we use the same firmware (bluenrg_6_3_Mode_2-16MHz.img) of the BlueNRG module.
Description of the problem:
When we try to send any command to the BLUENRG very often first byte of the SPI header (Ready byte) is not equal 0x02, which means that SPI is not ready. Often we need to do 8-10 attempts to send commands, which greatly reduces the throughput. When we run the same test on the Evaluation board (BlueNRG Eval Kit) the same problem does not occur when jumper JP1 (on the BlueNRG Eval Kit) is in 2-3 position (i.e. FTEST connected to VDD), if we set JP1 to 1-2 position (i.e. FTEST to GND) same problem occurs. Can you explain what the purpose of this jumper? Table 2 (DM0092683.pdf) shows that TEST10 (FTEST) must be connected to GND, is it right?