ADVANCE
CYW43570
The CYW43570 supports the USB hub and device model (USB, Revision 2.0, full-speed compliant).
When the hub is enabled, the CYW43570 handles all standard USB functions for the following devices:
■ HID keyboard
■ HID mouse
■ Bluetooth
All hub and device descriptors are firmware-programmable. This USB compound device configuration (see Figure 14) supports up to
three downstream ports. This configuration can also be programmed to a single USB device core. The device automatically detects
activity on the USB interface when connected. Therefore, no special configuration is needed to select HCI as the transport.
The hub’s downstream port definition is as follows:
■ Port 1 USB lite device core (for HID applications)
■ Port 2 USB lite device core (for HID applications)
■ Port 3 USB full device core (for Bluetooth applications)
When operating in hub mode, all three internal devices do not have to be enabled. Each internal USB device can be optionally enabled.
The configuration record in NVRAM determines which devices are present.
7.3.3 USB Full-Speed Timing
Table 13 shows timing specifications for the VDD_USB = 3.3V, VSS = 0V, and TA = 0°C to 85°C operating temperature range.
Table 13. USB Full-Speed Timing Specifications
Reference
Characteristics
Minimum
Maximum
Unit
1
Transition rise time
Transition fall time
4
20
20
ns
2
3
4
4
ns
Rise/fall timing matching
Full-speed data rate
90
111
%
12 – 0.25%
12 + 0.25%
Mbps
Figure 15. USB Full-Speed Timing
2
1
D+
90%
90%
VCRS
10%
10%
D-
7.4 UART Interface
The CYW43570 has a UART host interface for Bluetooth. The UART is a standard 4-wire interface (RX, TX, RTS, and CTS) with
adjustable baud rates from 9600 bps to 4.0 Mbps. The interface features an automatic baud rate detection capability that returns a
baud rate selection. Alternatively, the baud rate may be selected through a vendor-specific UART HCI command.
The UART has a 1040-byte receive FIFO and a 1040-byte transmit FIFO to support EDR. Access to the FIFOs is conducted through
the AHB interface through either DMA or the CPU. The UART supports the Bluetooth 4.1 UART HCI specification: H4, a custom
Extended H4, and H5. The default baud rate is 115.2 Kbaud.
The UART supports the 3-wire H5 UART transport, as described in the Bluetooth specification (Three-wire UART Transport Layer).
Compared to H4, the H5 UART transport reduces the number of signal lines required by eliminating the CTS and RTS signals.
The CYW43570 UART can perform XON/XOFF flow control and includes hardware support for the serial line input protocol (SLIP).
It can also perform wake-on activity. For example, activity on the RX or CTS inputs can wake the chip from a sleep state.
Document Number: 002-15054 Rev. *I
Page 32 of 94
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