SkyeModule Nova Datasheet
-
Preliminary
Page
|
30
Skyetek Inc
1732 Wazee St. Ste 202
Denver, CO 80202
www.skyetek.com
Main 720.328.3425 Fax:720.228.2400
The protocol for retrieving the response data is outlined below:
The SkyeModule Nova is half duplex so the response data must be retrieved after the request has been
sent.
The GPIO3_DR (data ready) signal will transition high when data is available for the host.
If data ready is not implemented on the host, the host can poll the module starting 1ms after the
command send is complete. The module will respond with 0x00 when no data is present, and 0x02 (start
of frame) when data is available.
Response data will be thrown away if not read within 10 seconds of becoming available.
The MISO signal provides the response data from SkyeModule Nova to the host.
To retrieve data on the MISO line, the SSEL (Slave Select) signal must be low when the clock is sent for an
entire byte. Between bytes, SSEL can either stay low or transition high again as long as it transitions
low before the first clock of the next byte.
The host can use the data length field (response bytes 2 and 3) in order to determine how many
bytes to read from the module as these first bytes will always be present immediately following a
start of frame (0x02).
Figure 10-7 below shows the timing required to retrieve data on the MISO line.
CLK
MISO
SSEL
Response
GPIO3_DR
Figure 10-7: SPI Response Timing
NOTE
–
Not reading the entire response before sending another command can cause undesired behavior. Always
make sure to read the entire response when using the SPI interface.