AvaLAN Wireless AW900mSPI-10 - Manual (Page 26)

AW900mSPI User’s Manual
PAGE 26 Technical support (650) 384-0000 www.avalanwireless.com
CHK0 to 15 is the 16-bit integer checksum value for the block. It is calculated in the
host microcontroller as follows:
1. Initialize a 16-bit register to 0x1911.
2. Add the 16-bit data value to the register beginning with the firmware block
number.
3. Perform a rotate left with no carry by 5 bit positions.
4. Repeat steps 2 and 3 for all 34 words (OFS and DATA).
Once all blocks have been submitted to the XC1220, then the host microcontroller
must issue the setFirmwareEnd (0x8C) command. Once the setFirmwareEnd com-
mand has been issued to the XC1220, the host microcontroller must wait for the
programming to complete. The XC1220 will indicate this by deasserting the Data
Ready line (pin 9). Once the Data Ready line is deasserted, programming is com-
plete and it is safe to reset the XC1220 with the setReset command (0x85). A reset
is required before the XC1220 will begin executing the new firmware image.
Programming Examples
Note that these examples apply to SPI mode.
Initialization Example
To initialize the XC1220 follow these steps:
1. At startup delay for 300 ms to allow the XC1220 enough time to initialize.
2. Assert /CS_BB (drive the line low) and issue
setNetworkKey (0x82) com-
mand and delay for 4 µs.
3. Send 3 bytes with 24-bit Network Key value.
4. Deassert /CS_BB (drive the line high) and delay for 6 µs.
5. Assert /CS_BB and issue
setPrivateKey (0x83) command and delay for 4 µs.
6. Send 16 bytes with 128-bit Private Key value.
7. Deassert /CS_BB and delay for 6 µs.
8. Assert /CS_BB and issue
setDeviceID (0x84) command and delay for 4 µs.
9. Send one byte indicating what type of device and ID number.
10. Deassert /CS_BB and delay for 6 µs.
11. Assert /CS_BB and issue
setStatus (0x81) command and delay for 4 µs.
12. Send one byte with bit 6 set to take radio out of standby mode.