presto_en.pdf - 第80页
Page 80 maximum load is sub stantially exceed ed for a certain time (this t ime is a djustable). PRESTO chec ks for the overload state t he who le time the po wer supply is connected . Support for an external pow er supp…
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voltage on pin -MCLR/VPP) or LVP (using the LVP pin).
The LVP programming algorithm can be disabled in the
device's configuration word. Microcontrollers have the
LVP algorithm enabled from the production, therefore
their PGM input needs to be treated during the first
programming (PGM input must be in log.0 for the time of
programming by means of the HVP algorithm).
Note: Not all devices have the PGM pin.
5.13.1 Pins Used for
Programming
This chapter describes how to treat pins in the ICSP
programming mode in accordance with the programming
algorithm.
HVP Algorithm
• PGM pin (if the device has one) must be maintained in
log.0!!
• -MCLR/VPP must be separated from the resetting
circuits (with a 10kΩ resistor, for example).
Aprogramming voltage is supplied to this pin P(VPP)
for programming. The leading edge and the voltage
level at VPP must not be influenced by the application.
The PRESTO programmer supports only fixed voltage
of 13V on pin P(VPP) in contrast to adjustable voltage
within a range of 6.5V to 17V supported by FORTE.
Please check limit voltage value on pin -MCLR/VPP of
the PIC device to be programmed by PRESTO.
• RB6 and RB7 pins must not be influenced by the
application during programming.
LVP algorithm (without VPP)
• RB6, RB7, PGM and -MCLR/VPP pins must not be
influenced by the application during programming. All
pins are in various logical levels during programming.
Loading of Different
Programmer Pins
The maximum current drawn from I/O pins, from pins
P(VPP) and VDD can be found in the Technical
Specification.
OTP (One-Time Programmable) devices have a
considerably higher current consumption on pin P(VPP)
than devices with a FLASH memory. Therefore the
application should not have any additional current
consumption at pin P(VPP) in case of OTP.
Data pins may have their signals changing at a speed of
several MHz, so the application must not influence the
signals in any significant way.
5.13.2 Power Supply Options
Connecting the shared data and power supply ground
(GND) is obviously necessary for all cases. The
microcontroller being programmed can be fed:
• externally from an application
• internally from a programmer
The external power supply from the application cannot be
used for some types of microcontroller having the -MCLR/
VPP pin alternatively configurable as an I/O.
The internal power supply can be used only in cases
where the application does not draw too much current
from programmer's feeding pin (VDD). The maximum
allowed current consumption can be found in the
Technical Specification.
Both PRESTO and FORTE programmers feature an
overcurrent protection. PRESTO has a software protection
in which an output gets disconnected by the running UP
program having detected an overload. FORTE has a
hardware protection, which does not depend on the
control software.
The programmer switches the power supply off if the
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maximum load is substantially exceeded for a certain
time (this time is adjustable). PRESTO checks for the
overload state the whole time the power supply is
connected.
Support for an external power supply is integrated in both
PRESTO and FORTE hardware. The programmer feeds the
input and output circuits with a voltage connected to pin
VDD. The voltage may be lower than 5V.
Advice
When designing the process, please pay special attention
to the type of device to be programmed – if it can be not
only operated but also programmed at a voltage lower
than 5V.
Power Supply Capacities in
Application
If there are capacities present at the application's power-
supply pin that would slow down the power on/off
switching and application is fed from programmer during
programming, longer charging/discharging times need to
be set in UP. In other case UP will probably announce
overcurrent on VDD pin.
An approximate time that should be set in the program:
t[μs] = 2.5 × C[μF] × R[Ω].
The equivalent resistance is presented in table following
table:
Programmer
Charging current
Discharging current
PRESTO
Corresponds to 50Ω
Corresponds to 1kΩ
FORTE
Corresponds to 50Ω
Corresponds to 27Ω
Table10: Equivalent resistance of pin VDD
Example
The necessary charging time for an application with
a33μF capacitor programmed with PRESTO:
2.5×33×50=4125μs
discharging:
2.5×33×1000=82.5ms.
For further information on the setting see
▸ Delay for VDD
switching on/off when supplied from programmer.
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Notes
• An error may occur if UP cannot program the
calibration word or if a fault occurs during Device ID
reading, UP warns about an overcurrent at VDD, etc.
This may be eliminated by prolonging the charging/
discharging time in the
▸ Delay for VDD switching on/
off when supplied from programmer
option - up to
several seconds.
• If UP points out an overcurrent error at VPP, a shorter
ICSP cable may help (its maximum length is 15cm).
5.13.3 ICSP Connector
All ASIX programmers use a unified connector with
2.54mm spacing of pins for programming with the ICSP
algorithm.
This connector has 8pins with 7signals. Not all signals
are always needed for the programming itself.
For further information on connecting a device to the
programmer see Connection Examples.
Pin No.
Signal
Programming connector
1
-MCLR
P / VPP
2
not used (key)
3
VCC
VDD
4
GND
GND
5
RB7
D / DATA
6
RB6
C / CLOCK
7
not used
8
RB3/RB4/RB5
L / LVP
Table11: ICSP connector
The following drawing illustrates the recommended
connection of -MCLR/VPP pin found in Microchip
microcontrollers for device programming through the
ICSP interface.
Fig.26: Recommended connection of -MCLR/VPP pin
5.14
Appendix C: Intel‑HEX
File Format
This appendix describes the format of Intel-HEX files used
by UP for data reading and saving. .hex is the typical
extension for such a file.
5.14.1 Supported
Alternatives of HEX
Files
UP supports 2 basic alternatives of Intel-HEX files:
• "basic", sometimes also 8-bit Intel-HEX File (e.g.
Microchip MPASMWIN generates this file with
parameter INHX8M).
• "extended", sometimes also 32-bit Intel-HEX File (e.g.
Microchip MPASMWIN generates this file with
parameter INHX32).