3
S P E C I F I C A T I O N S
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P I N D E F I N I T I O N S
The AC4868-250 has a simple interface that allows OEM Host communications with the transceiver. The table below
shows the connector pin numbers and associated functions. The I/O direction is with respect to the transceiver. All
inputs/outputs are 3.3VDC. All inputs are weakly pulled High and may be left floating during normal operation.
T a b l e 2 : A C 4 8 6 8 - 2 5 0 P i n D e f i n i t i o n s
Module
Pin
Type
Signal
Name
Function
1
O
GO0
Generic Output pin
2
O
TXD
Transmitted data out of the transceiver
I/O
RS485 A
(True)
Non-inverted RS-485 representation of serial data
3
I
RXD
Data input to the transceiver
I/O
RS485 B
(Invert)
Mirror image of RS-485 A
4
I
GI0
Generic Input pin
5, 16
GND
GND
Signal Ground
6
N/C
This pin has an internal connection and should be left disconnected.
7
O
CTS
Clear to Send – Active Low when the transceiver is ready to accept data for transmission.
8
I
RTS
Request to Send – When enabled in EEPROM, the OEM Host can take this High when it is not ready to
accept data from the transceiver. NOTE: Keeping RTS High for too long can cause data loss.
9
O
GO1
Generic Output pin
10
PWR
VCC1
3.3 – 5.5V, ±50mV ripple. Powers the radio’s uP. Draws ~30-50mA.
11
PWR
VCC2
3.3V, ±50mV ripple. Powers the radio’s power amplifier. Current draw depends on duty cycle and output
power.
12
I
Test
Test Mode – When pulled logic Low and then applying power or resetting, the transceiver’s serial interface
is forced to a 9600, 8-N-1 rate. To exit, the transceiver must be reset or power-cycled with Test Mode logic
High.
13
N/C
This pin has an internal connection and should be left disconnected.
14
I
GI1
Generic Input pin
15
I
UP_RESET
RESET – Controlled by the AC4868-250 for power-on reset if left unconnected. After a stable power-on
reset, a logic High pulse will reset the transceiver.
17
I
CMD/Data
When logic Low, the transceiver interprets OEM Host data as command data. When logic High, the
transceiver interprets OEM Host data as transmit data.
18
I
AD In
10 bit Analog Data Input
19
O
DA_Out
10 bit Analog Data Output
20
O
In_Range
When logic Low, a Client is in range of a Server on same Channel and System ID. Always low on a Server.
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