Datasheet

Note: The TX FIFO full check will happen for each GATT transaction (of up to 20 bytes of data each), so large data transfers may have multiple

200ms wait states.

You can use the AT+BLEUARTFIFO=TX (http://adafru.it/id3) command to check the size of the TX FIFO before sending data to ensure that you

have enough free space available in the buffer.

The TX FIFO has the following size, depending on the firmware version used:

Firmware <=0.6.6: 160 characters wide

Firmware >=0.6.7: 1024 characters wide

It IS possible with large data transfers that part of the payload can be transmitted, and the command can still produce an ERROR if the FIFO

doesn't empty in time in the middle of the payload transfer (since data is transmitted in maximum 20 byte chunks). If you need to ensure reliable

data transfer, you should always check the TX FIFO size before sending data, which you can do using the AT+BLEUARTFIFO command. If not

enough space is available for the entire payload, add a SW delay until enough space is available. Any single AT+BLEUARTTX command can fit

into the FIFO, but multiple large instances of this command may cause the FIFO to fill up mid transfer.

AT+BLEUARTTXF

This is a convenience function the serves the same purpose as AT+BLEUARTTX, but data is immediately sent in a single BLE packet ('F' for force

packet). This command will accept a maximum of 20 characters, which is the limit of what can be send in a single packet.

Codebase Revision: 0.7.6

Parameters: See AT+BLEUARTTX

Output: See AT+BLEUARTTX

AT+BLEUARTRX

This command will dump the UART service (http://adafru.it/iCn)'s RX buffer to the display if any data has been received from from the UART

service while running in Command Mode. The data will be removed from the buffer once it is displayed using this command.

Any characters left in the buffer when switching back to Data Mode will cause the buffered characters to be displayed as soon as the mode switch

is complete (within the limits of available buffer space, which is 1024 bytes on current black 32KB SRAM devices, or 160 bytes for the blue first

generation BLEFriend board based on 16KB SRAM parts).

Codebase Revision: 0.3.0

Parameters: None

Output: The RX buffer's content if any data is available, otherwise nothing.

You can also use the AT+BLEUARTFIFO=RX command to check if any incoming data is available or not.

https://learn.adafruit.com/introducing-the-adafruit-bluefruit-le-uart-

friend

Page 77 of 115