PNI CommBoard - Manual (Page 20)

PNI Sensor Corporation DOC#1018122 r02
PNI CommBoard User Manual Page 18
6 I
2
C Operation
The SpacePoint Scout and RM3100 Evaluation Board offer the option of using an I
2
C interface.
Refer to Figure 4-3 to configure the CommBoard for the desired interface. This section reviews
how to use the CommBoard to communicate using the I
2
C interface via a terminal emulation
program. If the user will employ the Scout‟s UART interface, then the CommBoard simply
passes the UART commands through the USB interface using the virtual communication port, as
discussed in Section 4.1. If the user will employ the RM3100 Evaluation Board‟s SPI interface,
refer to Section 5.
Note the I
2
C interface operates exclusively in hexadecimal, and the hexadecimal digits “a”
through “f” must be lower case. In addition to converting UART to I 2
C, the CommBoard allows
for monitoring the DRDY line. A summary of commands for working with an I
2
C interface is
given below.
Table 6-1: I
2
C Command Summary Table
Byte
Code
Command Syntax Response
{
Start of I
2
C Read
Command packet
{SLA REG NUM}
REG = Command or Register number in hex(uint8)
NUM = Number of bytes to read
}
Start I 2 C Read
Packet with STOP
HEX((uint8)data)
[
Start of I 2 C Write
Command Packet
[SLA REG data, data, data…..]
SLA = Slave 8-bit Address (R/W bit will be
overridden)
REG = Command or Register number (Uint8)
data = 8-bit data in 2-byte ASIC HEX format
]
Send I 2 C Write
Packet with STOP
,
Delimiters
Delimiters. Used to separate characters or data in
the return data string sent to the host.
~ Hold for DRDY ~#
Y,y Hold Always Y
Q Quit Hold Q
(Capital „Q‟ only)
F
Flush UART
Receive Buffer
F (Capital „F‟ only)
! Reset I 2 C !
& Set I 2 C clock &# where # = 0-A (single digit)
T,t Terminal Mode
Lower c ase „t‟ turns off terminal mode. Capital „T‟
turns on verbose terminal mode.