Tait TM8000 Series, Applications Manual, Page: 55 / 136

TM8000 3DK Hardware Developer’s Kit Application Manual Programmable I/O Lines 55
September 2003 © Tait Electronics Ltd
Configuration
1. Configure up to 5 input lines and associate them with this action.
Set the active state (high or low) and the debounce time (preset to
10 ms). Lines must be assigned in order, starting with pin 0 (LSB).
Unassigned signals are assumed to be logic 0.
2. Select BCD or BIN operation (BCD tab).
3. Enable or disable the front panel lockout as desired (BCD tab).
4. Configure a list of channels corresponding to the BCD or binary
values.
Timing
A fixed debounce time of 4ms is applied to all BCD inputs to ensure that all
lines have settled to their new state before being read. This is adequate for
logic-driven inputs but additional debounce time needs to be programmed
if a BCD switch or similar is used.
Description
When the current state of the BCD input lines is changed, the radio
determines the new channel according to
Table 3.3 and selects it for use.
When the radio is turned on, the BCD input lines are read. If the BCD
input lines are not set to zero, the radio will select the corresponding
channel. If they are set to zero, the radio will select the last saved channel.
If the bit pattern in BCD operation does not represent a valid BCD number
(from 01010 to 01111 and from 11010 to 11111), the radio will remain on
the current channel.
When the current state of the BCD input lines is changed while the radio
is in transmit mode, the channel change will be carried out as soon as the
radio returns to receive mode.
Related Actions
The ‘ Increment Channel ’ and ‘ Decrement Channel ’ input signals are used
to increment or decrement the current channel by one.
The ‘ Home Channel ’ input signal is used to change to a specified reference
channel, which can be used to increment or decrement from.