User's Manual

FLC-CBM202 Datasheet
Flaircomm Microelectronics Confidential
-19-
The same pin assignments are used for both SD SPI and CSPI as summarized in Table 4. Both the
SDIO protocols and CSPI provide access to the same functions and registers within the device; the
only difference is with the format of the commands used to perform these accesses.
4.5.2 Bluetooth UART Host Interfaces
CBM202 BT UART interface provides a simple mechanism for communicating with other serial
devices using the RS-232 protocol. UART_TX / UART_RX / UART_RTS / UART_CTS, the 4
signals, implement the UART function. When CBM202 is connected to another digital device,
UART_RX and UART_TX transfer data between the 2 devices. The remaining 2 signals,
UART_CTS and UART_RTS, implement RS232 hardware flow control where both are active low
indicators. If UART_CTS and UART_RTS are not required for hardware flow control, they are
reconfigurable as PIO. UART configuration parameters, such as baud rate and packet format, are set
using CBM202 firmware.
Note: To communicate with the UART at its maximum data rate using a standard PC, an accelerated
serial port adapter card is required for the PC.
The UART interface resets BT of CBM202 on reception of a break signal. A break is identified by a
continuous logic low (0V) on the UART_RX terminal, as the figure below shows. If t
BRK
is longer
than the value, defined by the PSKEY_HOSTIO_UART_RESET_TIMEOUT, a reset occurs. This
feature enables a host to initialize the system to a known state. Also, BT of CBM202 can issue a
break character for waking the host.
Figure 3: UART_TX Timing
4.5.2.1 UART Configuration While Reset is Active
The UART interface is tri-state while the BT is being held in reset. This enables the user to daisy
chain devices onto the physical UART bus. The constraint on this method is that any devices
connected to this bus must tri-state when BT of CBM202 reset is de-asserted and the firmware
begins to run.
4.6 Audio Interface
CBM202 provides a digital audio interface for BT, which is configurable as wither PCM or I2S port.
4.6.1 PCM Interface
The audio PCM interface on the CBM202 supports:
 Continuous transmission and reception of PCM encoded audio data over Bluetooth.
 Processor overhead reduction through hardware support for continual transmission and
reception of PCM data
 A bidirectional digital audio interface that routes directly into the baseband layer of the
firmware. It does not pass through the HCI protocol layer.