cancel
Showing results for 
Search instead for 
Did you mean: 

WICED Studio Bluetooth

New Contributor II

For some reason I have to connect CYBT-423028-EVAL HCI UART to a USB2TTY board which has NO CTS and RTS pin.

In one document of CYBT-423028-02, I see below description:

HCI UART Connections

The recommendations in this section apply to the HCI UART (Solder Pads 3, 4, 5, and 6). For full UART functionality, all UART signals must be connected to the Host device. If full UART functionality is not being used, and only UART RXD and TXD are desired or capable, then the following connection considerations should be followed for UART RTS and CTS:

■ UART RTS: Can be left floating, pulled low, or pulled high. RTS is not critical for initial firmware uploading at power on.

■ UART CTS: Must be pulled low to bypass flow control and to ensure that continuous data transfers are made from the host to the module.

Then I left RTS floating, and connect CTS to GND of USB2TTY board.

It turns out that I can not initialize the CYBT to work. But with a full UART it can work, so it should be a CTS/RTS issue.

Here's my setting:

RPi <===> cp2102 USB2TTY bridge board <===> tx/rx/GND 3 wire <===> BT board External HCI (J1)

Is there any way to make it work with only RXD/TXD?

0 Likes
Reply
1 Solution
Moderator
Moderator

Hi HaZh_4665521,

What I meant is, PUART can be used to send HCI command without using flow control, but then you need to define all the commands in your code manually. I don't think there is any other way for your application.

View solution in original post

3 Replies
Moderator
Moderator

Hi HaZh_4665521​,

If you are using HCI UART for downloading, then you must use flow control, means UART RTS & CTS pins. Refer Programming an EZ-BT WICED Module – KBA223428

Other way can be to use PUART to send HCI commands defined by yourself. These threads might be useful for you:

is hardware handshake must on HCI_UART lines?

Re: CYW920706WCDEVAL: Use PUART instead of USB

New Contributor II

Hi SheetalJ_96

I use HCI UART to make CYBT-423028 work as a BT HCI device in a system with an external host. Actually I have a third-party SDK board and I'm developping some bluetooth profiles on it, so I need a workable bluetooth controller. Unfortunately the mother board only has a UART without CTS/RTS pin.

I checked these reference threads you shared. There's some question:

  • Looks like he only try to bring up PUART interface to output some log, not HCI command.
  • He used a different board. I'm not sure the switch1 and switch5 he mentioned has the exactly same function as CYBT-423028-EVAL.
  • I checked app/hal code he used. It doesn't transfer PUART data to HCI. It still looks like a simple log output.

0 Likes
Reply
Moderator
Moderator

Hi HaZh_4665521,

What I meant is, PUART can be used to send HCI command without using flow control, but then you need to define all the commands in your code manually. I don't think there is any other way for your application.

View solution in original post