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3 Interfaces
3.1 USB interface
3.2 Interfaces to device
3.2.1 SMBus
8463A-AVR-11/11
The USB interface on the Atmel ATAVRBM300 module is USB Type B. The
ATAVRBM300 connects to a host computer via this interface. The ATAVRBM300 is
also powered by the USB port from the PC. The PC must deliver minimum 50mA to
power the ATAVRBM300. USB (USB 1.1, HID communication class) is used to
communicate between the PC and the ATAVRBM300. A PC USB driver is included in
Atmel AVR Battery Studio 2. This PC software must be installed before connecting
the ATAVRBM300 the first time.
The ATAVRBM300 supports four communication interfaces: SMBus/TWI, SPI, UART,
and single-wire UART. A 10-pin flat parallel cable includes all the signals from the
ATAVRBM300.
Table 3-1. Pins definition.
Pin number
Pin name
1
SDA
2
SCL
3
TXD
4
RWD
5
SCLK
6
MISO
7
MOSI
8
/SS
9
R/T
10
GND
Figure 3-1. 10-pin header definition.
To use the SMBus interface, three pins are required: SCL, SDA, and GND. SMBus
specification v1.1 is supported.
Description
SMBus data pin
SMBus clock pin
UART transmit pin
UART receive pin
SPI serial clock
SPI Bus Master input/Slave output
SPI Bus Master output/Slave input
SPI Slave select input
Single-wire UART transmit/receive pin
Ground
Atmel AVR390
3
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