MSK Modem
5
MX809
Pin
21
Signal
Serial Clock
22
Address Select
Description
This is the ‘C-BUS’ serial Clock input. This clock, produced by the
microcontroller, is used for transfer timing of commands and data to and from the
MSK Modem. See Section 6 and Section 7.1.4.
This pin enables two MX809s to be used on the same C-BUS, providing full-
duplex operation. When at a logic “1” Address/Command bytes (with the
exception of a General Reset) must have bit 3 set to a logic “1” to address this
device. See Table 5 and Table 6.
This input can be used to reactivate the MX809 from Powersave. The device will
be in Powersave when both this pin and bit 2 of the Control Register are set to
logic “1”. Recovery from Powersave is achieved by putting either the Wake pin or
the Powersave bit in the Control Register to logic “0”. This allows MX809
activation by the microcontroller or an external signal, such as R.S.S.I. or Carrier
Detect. See Table 3.
Positive supply. A single +5.0V power supply is required. Levels and voltages
within the MSK Modem are dependent upon this supply.
Table 1: Signal List
23
Wake
24
V
DD
TX Idle
RX SYNC Detect
RX Data Ready
TX Data Ready
RX Sync Detect
Interrupt outputs can be disabled by bit 3 of the Control Register
Table 2: IRQ Conditions
Powersave (CR bit 2)
1
0
1
0
Table 3:
Wake
1
1
0
0
MX809 Condition
Powersave
Enabled
Enabled
Enabled
Wake and Powersave Conditions
1998
MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
Doc. # 20480036.004
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
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