p89c668hbbd NXP Semiconductors, p89c668hbbd Datasheet - Page 65

• Manufacturer Part Number: p89c668hbbd
• Description: 80c51 8-bit Flash Microcontroller Family
• Manufacturer: NXP Semiconductors

Philips Semiconductors
In-System Programming (ISP)
The In-System Programming (ISP) is performed without removing
the microcontroller from the system. The In-System Programming
(ISP) facility consists of a series of internal hardware resources
coupled with internal firmware to facilitate remote programming of
the P89C660/662/664/668 through the serial port. This firmware is
provided by Philips and embedded within each
P89C660/662/664/668 device.
The Philips In-System Programming (ISP) facility has made in-circuit
programming in an embedded application possible with a minimum
of additional expense in components and circuit board area.
The ISP function uses five pins: TxD, RxD, V
Figure 56). Only a small connector needs to be available to interface
your application to an external circuit in order to use this feature.
The V
allowed to exceed datasheet limits.
Free ISP software is available on the Philips web site: “WinISP”
1. Direct your browser to the following page:
2. Download “WinISP.exe”
3. Execute WinISP.exe to install the software
Free ISP software is also available from the Embedded Systems
Academy: “FlashMagic”
1. Direct your browser to the following page:
2. Download Flashmagic
3. Execute “flashmagic.exe” to install the software
Using the In-System Programming (ISP)
The ISP feature allows for a wide range of baud rates to be used in
your application, independent of the oscillator frequency. It is also
adaptable to a wide range of oscillator frequencies. This is
accomplished by measuring the bit-time of a single bit in a received
character. This information is then used to program the baud rate in
terms of timer counts based on the oscillator frequency. The ISP
2002 Oct 28
80C51 8-bit Flash microcontroller family
16KB/32KB/64KB ISP/IAP Flash with 512B/1KB/2KB/8KB RAM
http://www.semiconductors.philips.com/products/standard/
microcontrollers/download/80c51/flash/
http://www.esacademy.com/software/flashmagic/
PP
supply should be adequately decoupled and V
Figure 56. In-System Programming with a Minimum of Pins
V
CC
SS
, V
CC
, and V
RST
XTAL2
XTAL1
V
SS
PP
not
PP
89C660
89C662
89C664
89C668
(see
P2.6, P2.7
65
V
TxD
RxD
V
CC
PP
feature requires that an initial character (an uppercase U) be sent to
the P89C660/662/664/668 to establish the baud rate. The ISP
firmware provides auto-echo of received characters.
Once baud rate initialization has been performed, the ISP firmware
will only accept Intel Hex-type records. Intel Hex records consist of
ASCII characters used to represent hexadecimal values and are
summarized below:
In the Intel Hex record, the “NN” represents the number of data
bytes in the record. The P89C660/662/664/668 will accept up to 16
(10H) data bytes. The “AAAA” string represents the address of the
first byte in the record. If there are zero bytes in the record, this field
is often set to 0000. The “RR” string indicates the record type. A
record type of “00” is a data record. A record type of “01” indicates
the end-of-file mark. In this application, additional record types will
be added to indicate either commands or data for the ISP facility.
The maximum number of data bytes in a record is limited to 16
(decimal). ISP commands are summarized in Table 14.
As a record is received by the P89C660/662/664/668, the
information in the record is stored internally and a checksum
calculation is performed. The operation indicated by the record type
is not performed until the entire record has been received. Should
an error occur in the checksum, the P89C660/662/664/668 will send
an “X” out the serial port indicating a checksum error. If the
checksum calculation is found to match the checksum in the record,
then the command will be executed. In most cases, successful
reception of the record will be indicated by transmitting a “.”
character out the serial port (displaying the contents of the internal
program memory is an exceptions).
In the case of a Data Record (record type 00), an additional check is
made. A “.” character will NOT be sent unless the record checksum
matched the calculated checksum and all of the bytes in the record
were successfully programmed. For a data record, an “X” indicates
that the checksum failed to match, and an “R” indicates that one of
the bytes did not properly program. It is necessary to send a type 02
record (specify oscillator frequency) to the P89C660/662/664/668
before programming data.
:NNAAAARRDD..DDCC<crlf>
P89C660/P89C662/P89C664/
+5V
TxD
RxD
V
“1”
+ 5V (+12V Tolerant)
SS
SU01265
P89C668
Product data