Wireless Modem Data Pump
FX909A
TSB - Transmit Single Byte
This task takes a byte from the Data Buffer and transmits the 8 bits, bit 7 first.
Once the modem has read the data byte from the Data Buffer, the BFREE and IRQ bits of the Status
Register will be set to '1', indicating to the µC that it may write the next task and its data to the
modem.
TSO - Transmit Scrambler Output
This task, intended for channel set-up, enables the scrambler and transmits its output.
When the modem has started the task the Status Register bits will not be changed and hence an IRQ
will not be raised. The µC may write the next task and its data to the modem at any time and the
scrambler output will stop when the new task has produced its first data.
RESET - Stop any current action
This task takes effect immediately, and terminates any current action (task, AQBC or AQLEV) the
modem may be performing and sets the BFREE bit of the Status Register to '1', without setting the
IRQ bit. It should be used when V is applied to set the modem into a known state.
DD
Note that due to delays in the internal switched capacitor filter, it will take approximately 3 bit times
for any change to become apparent at the TXOP pin.
Task Timings
The device should not be given a new task for at least 2 bit times after the following:
Changing from powersave state to normal operation.
Changing the Tx/Rx bit.
Resetting or after power is applied to the device.
This is to ensure that the internal operation of the device is initialised correctly for the new task. Note
that this only applies to the Command Register, the other registers may be accessed as normal.
ã 1996 Consumer Microcircuits Limited
19
D/909A/4
CMLMICRO [ CML MICROCIRCUITS ]
