SkyeModule Nova Datasheet
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Preliminary
Page
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32
Skyetek Inc
1732 Wazee St. Ste 202
Denver, CO 80202
www.skyetek.com
Main 720.328.3425 Fax:720.228.2400
The communication scheme from host to module is as follows:
Initiate a start condition (SDA transitions low while SCL is high).
Send the nine bits of the initial start packet as follows:
o
Send the 7-bit address.
o
Send a write bit as the eighth bit (0 for writing from the host to the slave).
o
Send the ninth bit
as the “acknowledge” bit (ACK)
o
If the reader recognizes the address, it pulls SDA low to acknowledge
Use the bus to clock each byte of the SkyeTek protocol request.
After sending the entire request, initiate a stop condition. (SCL transitions high, and then SDA transitions
high while SCL is high)
Wait for command to complete:
The GPIO3_DR (data ready) signal will transition high when data is available for the host to read.
If data ready is not implemented on the host, the host can poll the module after the request is sent. The
module will NAK to a read while it is busy executing a command.
Communication scheme from module to host is as follows:
Initiate a start condition. (SDA transitions low, and then SCL transitions low.)
Send the nine bits of the initial start packet as follows:
o
Send the 7-bit address.
o
Send a read bit as the eighth bit (1 for reading from the slave to the host).
o
Send the ninth bit as the “acknowledge” bit (ACK)
o
If the reader recognizes the address, it pulls SDA low to acknowledge
o
If the address isn’t recognized or the module is busy the SDA bit will remain
high during the ACK
bit.
Clock each byte of the SkyeTek protocol response from the module.
After receiving the response, is received, initiate a stop condition. (SDA transitions high while SCL is high.)
SDA must transition while the clock is low and remain stable while the clock is high.
Response data will be thrown away if not read within 10 seconds of becoming available.
Recommended response handler method #1 (polling):
Read a single byte continuously until the reader ACKs and a 0x02, start of frame is received
Read two bytes which contain the message length
Read the remaining message length
Recommended response handler method #2 (using data ready signal):
Poll on the data ready signal until it transitions high, indicating that data is present
Read three bytes, the last two contain the message length
Read the remaining message length