User's Manual

ACG HF Multi ISO RFID Reader V1.0
ACG Identification Technologies GmbH 39
11.1.4 Electrical characteristics of J2 PINs
PIN PIN No. Min Typ. Max. Description
RX 11 USART-
TTL
1
25 mA RX to PC
To RS232, RS485 or RS422
device driver
TX 12 USART-
TTL
1
25 mA TX to PC
To RS232, RS485 or RS422
device driver
DIR 13 TTL 25 mA Direction of RS 485
Logic High = Reader to Host
Logic Low = Host to Reader
USER 14 TTL
2
25 mA User Port
MCLR 15 TTL
3
Master clear
Leave unconnected.
Low will reset the register
and the key management to
default values.
EN 16 ST
4
25 mA Enable reader
logic low will disable the
reader
Open or logic high
VDD
min
@ 25mA
VDD
typ
@ 11mA
VDD
max
@ 0 mA
LED red
Output Voltage
LEDr 17
11mA 25mA External Resistor
min. 200 Ω
1.4V
@ 11mA
VDD
@ 0mA
LED green (reading LED)
with 330 Ω (internal serial)
resistor
LEDg 18
11mA 15mA
GND 19 GND Ground
VDD 20 +4.5V +5.0V +5.5V Supply Voltage
IDD 32 mA 150 mA 250 mA Supply Current (Without
SAM)
Figure 11-4: Electrical characteristics of pins
1
Universal Synchronous Asynchronous Receiver Transmitter
2
TTL buffer output / input
3
Voltage spikes below GND at the MCLR/V
DD
pin, including currents greater than 80mA, may cause
latch-up. Thus, a series resistor of 50-100Ω should be used when applying a "low" level to the
MCLR/V
DD
, rather than pulling this pin directly to GND.
4
Schmitt trigger buffer input