
Smart Modular Technologies
Specification ASY90147-1&2
December 10, 2002
Smart Modular Technologies
10
10. UART Interface
The Universal Asynchronous Receiver Transmitter (UART) interface provides a mechanism
for communicating with other serial devices using the RS232 standard. When the module is
connected to another digital device, UART_RX and UART_TX transfer data between the
two devices. The other two signals, UART_CTS and UART_RTS, can be used to implement
RS232 hardware flow control where both are active low indicators.
Table 5. Possible UART Settings
Parameter
Possible Values
1200 Baud (
≤
2% Error)
9600 Baud (
≤
1% Error)
1.5MBaud (
≤
1% Error)
RTS/CTS or None
None, Odd or Even
1 or 2
8
Minimum
Baud Rate
Maximum
Flow Control
Parity
Number of Stop Bits
Bits per channel
11. USB Interface
The Universal Serial Bus (USB) interface on the module provides a full-speed (12Mbits/s)
data throughput, capable of driving a USB cable directly. No external USB transceiver is
required. The device operates as a USB peripheral, responding to requests from a master
host controller such as a PC. Both the OHCI and the UHCI standards are supported. Only
the USB slave operation is supported.
Table 6. USB Data Connections
USB Connections
Function
D-
D+
“Differential” 0
“Differential” 1
12. PCM
Pulse Code Modulation (PCM) is the standard method used to digitize human voice patterns
for transmission over digital communication channels. The module has hardware support for
continual transmission and reception of PCM data, thus reducing processor overhead for
wireless headset applications. The module offers a bi-directional digital audio interface
routes directly into the basedband layer of the on-chip firmware. Up to three SCO
connections can be supported by the PCM interface at any one time.
The PCM interface can be configured as Master or Slave. When it operates as the PCM
interface Master, it generates an output clock of 128, 256 or 521kHz. When configured as