Table of Contents
Advertisement
4.5 Programmer / Target System Power Supply Schematic
The schematic shown in fig. 4.5 details the possible power supply scenarios for powering both the
programmer and the Target System.
The key points to note are as follows:
•
The programmer can be powered from an external power supply (9.0 – 12.0V DC regulated)
via either the 'DC Jack Socket (J6)' or the 'DC Molex Connector (J15)'
•
The programmer can power the Target System with a user-specified voltage from 3.0 – 5.0V
via the 'Programmer Controlled Power Supply'.
•
The programmer 'Line Driver Circuitry' must always be powered at the same voltage as the
Target System. This ensures that the logic levels generated from the programmer are
compatible with the logic levels on the Target System.
•
The external link 'LK1' is a virtual link. It simply represents that the Vcc connection between
the programmer and Target Vcc is broken.
fig. 3.2.1. Explanation of all Power Supply Circuit Schematic labels
#
Item
Description
1
V_PSU_EXT
2
GND
3
V_Target
4
LK1
4
I/O Level
Converter /
Driver Circuit
5
Target Load
6
Bench Power
Supply
60
•
This is the voltage applied from an external power supply (9.0 – 12.0V
DC regulated) via either the 'DC Jack Socket (J6)' or the 'DC Molex
Connector (J15)'
•
This is the common ground of the programmer which is connected to
J6/J15 GROUND and also to the TARGET GROUND via one of the
ISP Headers.
•
This is the voltage measured between the Vcc and Ground of the
Target System.
•
This is a virtual link (does not really exist) signifying the cable between
the Programmer TVCC and the Target System Vcc.
•
If the programmer and Target System are independently powered,
then LK1 must be not fitted i.e. the Target System Vcc wire should not
be connected to the programmer TVCC connection.
•
This is the circuitry which translates the 5.0V I/O signals from the
programmer 'Supervisor Microcontroller' to the Target System voltage
levels.
•
The supply to the 'I/O Level Converters' must be at the same voltage
as the Target System. I.e. if the Target System is powered at 3.3V,
then the 'I/O Level Converters' must also be powered at 3.3V.
•
This is the load presented to the programmer across the PROG_VCC
and GROUND terminals of any ISP Header.
•
This simply indicates a stable DC power supply with a current limit
facility.
PPM3 MKII Programmer - User Guide - V1.04 - 10
th
May 2008
Advertisement
Table of Contents
