Aardvark Paylink Lite 2 User manual

Paylink Lite 2
User Manual
Author: Andy Graham
Issue: 1.1
Date: 3rd August 2018
Copyright © Aardvark Embedded Solutions Ltd. 2018. All rights reserved.

ccTalk Paylink Lite 2 User Manual Aardvark Embedded Solutions Ltd.
Issue 1.1 3rd August 2018 Page 2
1 Introduction
The Paylink Lite 2 family comprises a set of interface boards, primarily
intended to allow the connection of money handling peripheral equipment to
PCs running a Windows operating system or Linux.
At time of writing, the Paylink Lite 2 family currently comprises the following
boards.
ccTalk Standard
RS232 Standard
Paylink Lite 2 is designed to interface either RS232 money handling
peripherals or ccTalk peripherals to a PC.
An MDB interface variant is currently being considered, but is not available.
All variants of the Paylink Lite 2 have onboard circuitry designed to prevent
“hanging” of the PC USB electronics due to noise.
This document serves as the user manual for the ccTalk Paylink Lite 2.

ccTalk Paylink Lite 2 User Manual Aardvark Embedded Solutions Ltd.
Issue 1.1 3rd August 2018 Page 3
1.1 Intended Audience
The document is intended as a product description to engineers intending to
use the Paylink Lite 2 in their equipment.
The document gives full descriptions of the operation and physical
connections to the ccTalk Paylink Lite 2.
A description of the high-level Paylink Applications Program Interface (API) is
outside the scope of this document, but see section 1.3, “Document
References” for the document describing the Paylink API.
1.2 Revision History
Issue
Date
Auth
Description
1.0
31st July 2012
AJG
First complete issue.
1.1
3rd Aug 2012
AJG
Altered pin definitions of the 20-
pin digital I/O connector to match
the documentation of other
Paylink boards.
1.3 Document References
The Paylink Lite 2 family of interface boards implement a subset of the full
Paylink API.
This API provides high-level, device-independent control of money handling
peripherals and digital I/O signals.
Use of this API means that the machine manufacturer’s software engineers
have no communication protocol software to write. Instead, they make high-
level calls into the API, that provide all necessary information regarding the
arrival of cash and control of payment devices.
The description of the Paylink API is outside the scope of this document.
This document is therefore intended to be read in conjunction with the
standard Paylink reference documents.

ccTalk Paylink Lite 2 User Manual Aardvark Embedded Solutions Ltd.
Issue 1.1 3rd August 2018 Page 4
2 Table of Contents
1Introduction ....................................................................................................................... 2
1.1 Intended Audience........................................................................................................ 3
1.2 Revision History............................................................................................................ 3
1.3 Document References.................................................................................................. 3
2Table of Contents.............................................................................................................. 4
3Board Layout..................................................................................................................... 5
3.1 J0101 –Power Connector............................................................................................ 6
3.2 J0102 –Digital I/O Connector ...................................................................................... 7
3.2.1 Input Signal Operation......................................................................................... 8
3.2.2 External LED Driver Operation ............................................................................ 8
3.2.3 Output Signal Operation ...................................................................................... 8
3.3 J0201 –USB Connector............................................................................................... 8
3.4 J0501 –ccTalk Connector............................................................................................ 9
3.5 J0501 –RS232 Connector ......................................................................................... 10
3.5.1 Connecting to a 9-Pin Male D-Type................................................................... 10
4USB Reset and LED Operation ...................................................................................... 11
4.1 USB Reset Strategy ................................................................................................... 11
4.2 Onboard LED Operation............................................................................................. 12

ccTalk Paylink Lite 2 User Manual Aardvark Embedded Solutions Ltd.
Issue 1.1 3rd August 2018 Page 5
3 Board Layout
The ccTalk Paylink Lite 2 circuit boards appear as in the following diagram.
Each connector will now be described in its own section, followed by a section
describing the onboard LED operation.
Note that although a power connector is provided, most of the electronics on
the Paylink Lite 2 board will operate from the USB power supply.
Thus, even though the onboard LED is illuminated, this does not necessarily
mean that the board is correctly powered.
Pin 1
Pin 1
Pin 1
Pin 2
Pin 20
J0202
J0201
J0101
J0501
J0102
+-
LED
ccTalk
Standard

ccTalk Paylink Lite 2 User Manual Aardvark Embedded Solutions Ltd.
Issue 1.1 3rd August 2018 Page 6
3.1 J0101 –Power Connector
The power connector on all variants of the Paylink Lite 2 is a two-pin JST
connector. This should be connected to a twelve volt supply.
Pin
Signal Name
Description
1
+12 Volts
12 Volt supply to Paylink Lite 2
2
0 Volts
0 Volt supply to Paylink Lite 2
This 12 Volt supply is primarily used to supply power to the (12 Volt) ccTalk
peripherals; the 12 Volt supply passes through a 3A fuse and is made
available at the ccTalk connector. See section 3.4, “J0501 –ccTalk
Connector”. It is also connected to allow simple supply to the digital outputs. If
neither are in use, then there is no need to connect this.
For RS232 this can be connected to a suitable power supply for use in
supplying digital outputs. If no outputs (or only LED outputs) are being driven,
then there is no need to connect this.)

ccTalk Paylink Lite 2 User Manual Aardvark Embedded Solutions Ltd.
Issue 1.1 3rd August 2018 Page 7
3.2 J0102 –Digital I/O Connector
The pinout of the I/O connector on all Paylink Lite 2 boards is the same.
Board Edge
In order to maintain compatibility with
earlier versions of Paylink, the pin
allocation of this connector is as
shown in the diagram to the left.
Note that this does not match the pin
allocation described in the Molex
Microfit documentation.
Pin
Signal Name
Description
1
+12 VF
Twelve Volt (Fused) signals for use with
output signals.
2
+12 VF
3
+12 VF
4
+12 VF
5
Output 0
Output signal 0 (Active Low).
6
Output 1
Output signal 1 (Active Low).
7
Output 2
Output signal 2 (Active Low).
8
Output 3
Output signal 3 (Active Low).
9
Pull-Up 0
Pull-ups to the USB 5V to allow the direct
driving of LEDs.
10
Pull-Up 1
11
Pull-Up 2
12
Pull-Up 3
13
Ground
Ground reference signals for use with
input signals.
14
Ground
15
Ground
16
Ground
17
Input 0
Switch input 0.
18
Input 1
Switch input 1.
19
Input 2
Switch input 2.
20
Input 3
Switch input 3.

ccTalk Paylink Lite 2 User Manual Aardvark Embedded Solutions Ltd.
Issue 1.1 3rd August 2018 Page 8
3.2.1 Input Signal Operation
A switch across an input and its corresponding ground reference will be
detected by Paylink Lite 2.
3.2.2 External LED Driver Operation
The board is designed to drive LEDs directly, using the USB supply. The
current limit resistors fitted to each board are such that a nominal 10 mA is
supplied to each LED when the output is driven.
To attach an LED, the Anode (+) of the LED should be connected to an
appropriate “Pull Up” (on pins 9, 10, 11 or 12) and the Cathode (-) of the LED
should be connected to the drive output (on pins 5, 6, 7 or 8).
3.2.3 Output Signal Operation
Each standard output is designed to drive a maximum 100 mA, non-inductive
load.
3.3 J0201 –USB Connector
The connection from the PC to the Paylink Lite 2 board is though a standard
“Type B” connector.
Although an entirely standard connector, for completeness, its pin out is
included here.
Pin
Signal Name
Description
1
+12 Volts
12 Volt supply to Paylink Lite 2
2
USB Data -
Negative USB data signal.
3
USB Data +
Positive USB data signal.
4
0 Volts
0 Volt supply to Paylink Lite 2
5
6

ccTalk Paylink Lite 2 User Manual Aardvark Embedded Solutions Ltd.
Issue 1.1 3rd August 2018 Page 9
3.4 J0501 –ccTalk Connector
The ccTalk connector on the ccTalk Paylink Lite 2 is a six-pin Molex Microfit
connector, with the same pinout as the original Paylink.
In order to maintain compatibility with
earlier versions of Paylink, the pin
allocation of this connector is as
shown in the diagram to the left.
Note that this does not match the pin
allocation described in the Molex
Microfit documentation.
Pin
Signal Name
Description
1
ccTalk Data
This is the bidirectional ccTalk data signal.
2
+12 VF
This is the fused twelve volt supply to the
ccTalk peripherals.
3
Ground
This is the ground connection to the
twelve Volt peripherals.
4
+24 VF
This is the fused twenty-four volt supply to
the ccTalk peripherals.
5
Ground
This is the ground connection to the
twenty-four Volt peripherals.
6
+24 Volts In
This is the incoming twenty-four Volt
supply to the ccTalk peripherals.
Note that both the outgoing twelve volt and twenty-four volt supplies are fused
at 3A onboard the Paylink Lite 2.

ccTalk Paylink Lite 2 User Manual Aardvark Embedded Solutions Ltd.
Issue 1.1 3rd August 2018 Page 10
3.5 J0501 –RS232 Connector
The ccTalk connector on the ccTalk Paylink Lite 2 is a six-pin Molex Microfit
connector, with the same pinout as the original Paylink.
In order to maintain compatibility with
earlier versions of Paylink, the pin
allocation of this connector is as
shown in the diagram to the left.
Note that this does not match the pin
allocation described in the Molex
Microfit documentation.
Pin
Signal Name
Description
from
to
to
from
3.5.1 Connecting to a 9-Pin Male D-Type
A common connection standard for RS232 peripherals is for the peripheral to
be fitted with a 9-way, female, D-Type connector.
Thus a cable from the Paylink Lite 2 to a male D-Type is commonly required.
This needs to be wired as follows:
Molex Microfit
Connector
Signal
Name
Description
9-Way Male D
Type Connector
from
to
to
from
or

ccTalk Paylink Lite 2 User Manual Aardvark Embedded Solutions Ltd.
Issue 1.1 3rd August 2018 Page 11
4 USB Reset and LED Operation
4.1 USB Reset Strategy
Each variant of the Paylink Lite 2 family is fitted with a very simple
microcontroller.
The primary purpose of this microcontroller is to manage the USB connection
to the PC.
PC USB circuitry is “fragile” and the connection of physical peripherals
through a USB link can induce noise within the PC. This noise can cause the
PC operating system to “hang”.
The approach that Paylink Lite 2 takes is to detect failures in the USB
communications system. On detecting these failures, the Paylink Lite 2
automatically disconnects itself from the USB bus and reconnects itself a
short time later.
This technique, effectively resetting the USB, has shown itself to be very
effective in fixing any USB link hanging.
At start of world, there is a five-minute period where the microcontroller does
not check for regular activity. If regular activity is detected, then no reset is
applied to the FTDI device.
After that period, if no activity is detected, then the microcontroller enters a
cycle of four timing patterns, with "off" and "on" timings as follows:
1. 5 seconds Off 30 seconds On
2. 10 seconds Off 60 seconds On
3. 15 seconds Off 90 seconds On
4. 20 seconds Off 120 seconds On
Whenever the microcontroller gets to the fourth timing pattern, it “sticks” there
until activity is detected.

ccTalk Paylink Lite 2 User Manual Aardvark Embedded Solutions Ltd.
Issue 1.1 3rd August 2018 Page 12
4.2 Onboard LED Operation
The onboard LED flashes at a nominal 1 Hz, and the different mark-space
ratios serve to indicate what the microcontroller is doing.
90% Mark-Space Ratio
When the LED is illuminated for 90% of the cycle, the microcontroller is
indicating that the USB traffic is normal.
The USB device is free to run normally.
50% Mark-Space Ratio
When the LED is illuminated for 50% of the cycle, the microcontroller is
indicating that the USB traffic has “just” ceased and that it is attempting
to reset the USB bus.
10% Mark-Space Ratio
When the LED is illuminated for 10% of the cycle, the microcontroller is
indicating that the USB traffic has failed for some time. It is attempting
to reset the USB bus, but at a much longer cycle time than when the
traffic first failed.