GMSK Modem Data Pump
Page 25 of 37
MX909A PRELIMINARY INFORMATION
START
Write 6 bytes of
Frame Head to
Data Buffer
Write Task = 'RESET'
to Command Register
Write 18 bytes of
data to Data buffer
Set
C
Wait 2-bit times for
lowpass filter
to settle
Write Task = TDB
to Command Register
Data Block Counter
to length of message
Write CKDIV, HI/LO,
and DARA values to
Control Register
Wait for IRQ line
to go low then
execute Tx I.S.R.
Write Task = 'T7H'
to Command Register
Write IRQEN = '1'
SCREN = '1', TX/RX = '1'
to Mode Register
Wait for IRQ line
to go low then
execute Tx I.S.R.
Decrement
Data Block Counter
C
No
No
Data Block
Counter = '0'?
Data Block
Counter = '0'?
Read Status Register
BFREE = '1'?
Yes
Yes
Write 'Hang Byte'
to Data Buffer
No
Yes
Tx Interrupt Service Routine (I.S.R.)
Write Task = 'TSB'
to Command Register
Read Status Register
FINISH
No
Service other interrupts
IRQ bit = '1'?
Yes
Yes
No
Fault detected:
Abort transmission
IBEMPTY = '1'?
No
Fault detected:
Abort transmission
BFREE = '1'?
Yes
Figure 14: Transmit Process Flow Chart
¤2001 MX-COM, Inc.
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
Doc. # 20480134.005
All trademarks and service marks are held by their respective companies.
CMLMICRO [ CML MICROCIRCUITS ]
