Data Sheet

AC4790
Datasheet
https://www.lairdconnect.com/
9
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4 HARDWARE
4.1 AC4790 Pinout
The AC4790 has a simple interface that allows OEM host communications with the transceiver. Table 4 shows the connector
pin numbers and associated functions. The I/O direction is with respect to the transceiver. All outputs are 3.3 VDC levels and
inputs are 5 VDC TTL (with the exception of AC4790-1x1 and AC4790-1000 transceivers, which have 3.3 V inputs). All inputs
are weakly pulled High and may be left floating during normal operation (with the exceptions listed for the AC4790-1x1).
Table 4: AC4790 Pinout
Pin #
1x1 Pin
Type
Signal Name
Function
1
4
O
GO0
Session status if Protocol Status is enabled. Otherwise, generic
output.
2
6
O
TXD
Transmitted data out of the transceiver
I/O
RS485A (True)
1
Non-inverted RS485 representation of serial data
3
7
I
RXD
Data input to the transceiver
I/O
RS485B(Invert)
1
Mirror image of RS485A
4
5
2
GI0
Generic Input pin
5
3
GND
GND
Signal Ground
6
O
Do Not Connect
Has internal connection, for Laird use only.
7
9
O
CTS
Clear-to-Send – Active Low when the transceiver is ready to
accept data for transmission.
8
10
2
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
19
O
GO1
Received Acknowledge status pin if Protocol Status is enabled.
Otherwise, generic output.
10
2
PWR
VCC1
AC4790-1x1: 3.3V, ±50mV ripple
AC4790-200: 3.3 – 5.5V, ±50mV ripple
(Pin 10 is internally connected to Pin 11)
AC4790-1000: 3.3 – 5.5V, ±50mV ripple
11
11
PWR
VCC2
AC4790-1x1: 3.3V, ±50mV ripple
AC4790-200: 3.3 – 5.5V, ±50mV ripple
(Pin 11 is internally connected to Pin 10)
AC4790-1000: 3.3V ±3%, ±100mV ripple
12
23
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
12
O
RSSI
Received Signal Strength - An analog output giving an
instantaneous indication of received signal strength. Only valid
while in Receive Mode.
14
21
2
I
GI1
Generic Input pin