1200/2400bps MSK Modem for Trunked Radio Systems
12
MX429A
5.3 Transmit Operation
(a) Tx - one message with checksum supplied by host
Tx ENABLE
(2)
(1)
Tx INPUT
P1
P2
Pn
S1
S2
A1
A2
A3
A4
A5
A6
C1
C2
H
(2)
(3)
IRQ OUTPUT
Tx DATA
READY
WRITE TO Tx
DATA BUFFER
S1
S2
A1
A2
A3
A4
A5
A6
C1
C2
READ STATUS REGISTER
Tx PARITY
ENABLE
Tx IDLE
(b) Tx - one message with checksum generated internally
Tx ENABLE
(2)
(1)
Tx INPUT
P1
P2
Pn
S1
S2
A1
A2
A3
A4
A5
A6
C1
C2
H
(2)
(3)
IRQ OUTPUT
Tx DATA
READY
WRITE TO Tx
DATA BUFFER
S1
S2
A1
A2
A3
A4
A5
A6
READ STATUS REGISTER
Tx PARITY
ENABLE
Tx IDLE
(c) Tx - more than one message, with checksum generated internally
Tx ENABLE
(2)
Tx INPUT
P1
P2
Pn
S1
S2
A1
A2
A3
A4
A5
A6
C1
C2
S1
S2
A1
A2
A3
A4
A5
A6
C1
C2
S1
IRQ OUTPUT
Tx DATA
READY
WRITE TO Tx
DATA BUFFER
S1
S2
A1
A2
A3
A4
A5
A6
S1
S2
A1
A2
A3
A4
A5
A6
S1
READ STATUS REGISTER
Tx PARITY
ENABLE
Tx Parity Enable is 'Low' - indicating that the
SYNC/SYNT word is not to be included in the
next checksum
A6
C1
C2
D1
D2
D3
D4
D5
D6
C1
C2
H
Tx INPUT
Notes:
A
C
D
H
P
-
-
-
-
-
-
-
-
-
Address Code
Checksum
Data Code
Hang Bit
Preamble
SYNC/SYNT
Tx Output at bias level
Tx Output at High Impedance
If Tx Data Ready is Set here, it inhibits Tx Data Ready
Interrupt - The Tx Idle Interrupt occurs 1 bit later
IRQ OUTPUT
Tx DATA
READY
S
(1)
(2)
(3)
WRITE TO Tx
DATA BUFFER
D1
D2
D3 D4 D5
D6
READ STATUS
REGISTER
Tx PARITY
ENABLE
Tx Parity Enable remains 'High' - indicating that
all following data is to be included in the checksum
Tx IDLE
Figure 6: Transmit Operation
© 1998 MX-COM Inc.
www.mxcom.com Tel: 800 638-5577 336 744-5050 Fax: 336 744-5054
Doc. # 20480128.007
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
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