P8XC557E4 NXP Semiconductors, P8XC557E4 Datasheet - Page 58

• Manufacturer Part Number: P8XC557E4
• Description: The P80C557E4/P83C557E4/P89C557E4 (hereafter generically referred to as P8xC557E4) single-chip 8-bit microcontroller is manufactured in an advanced CMOS process and is a derivative of the 80C51 microcontroller family
• Manufacturer: NXP Semiconductors

Philips Semiconductors
8.6 Serial Programming of FEEPROM
Serial in-circuit programming (boot-mode) is entered if during and
after RESET PSEN and EA are pulled down, PSEN via a resistor of
3.3 k Ohm to VSS. The two UBS bits are set to 1 by hardware and
program execution starts at 0000H of the boot ROM. P3.0 (RXD)
and P3.1 (TXD) form the serial RS232 interface. A baud rate of 4800
or 9600 Baud is possible, if the PLL oscillator is selected. The
receive and transmit channel have the same baudrate. The format
is: Startbit, 8 data bits (last bit always 0), no parity bit and at least
one stopbit. The boot routine inputs the Intel Hex Object Format.
The baud rate will be selected automatically after reception of the
first character (:) of the object file. No other characters are allowed
to preceed the first (:) character. Programming is only started if the
first received record has the right type indication (TT). If the security
feature is activated (contents of the security byte = 50H) then the
programming starts with a Full Erase, otherwise only the addressed
page(s) will be erased and the not altered bytes are rewritten.
During the erase or write operation the next string of bytes can be
received. Xon and Xoff handshake codes are used to control the
serial transfer. At the end of the programming a message that
indicates a successful or not successful programming, will be
returned over the RS232 interface channel. If the programming was
successful then the user program can be started up at 0000H in
FEEPROM by a reset for user mode (EA = high, PSEN not
affected). If the programming was not successful the boot program
halts and a retry can be started by a reset for the boot mode.
1999 Mar 02
1) Alternative XTAL1, 2 may be selected (SELXTAL1 = 1)
Single-chip 8-bit microcontroller
ALL OTHER
PINS ARE
DON’T
CARE
32.768 kHz
Figure 54. Serial programming (boot mode) Configuration
0
1)
XTAL3
XTAL4
RST
SELXTAL1
P89C557E4
58
V
V
SS
+5 V
DD
P83C557E4/P80C557E4/P89C557E4
1.
8.7 Boot Routine
The boot routine transmits the next “one ASCII character” messages
via the RS232 interface:
No messages are transmitted if the baud rate of the first character
(:) can not be detected.
The boot routine can also be started by the internal or external user
program (LJMP FC07H). FMCON must be loaded previously with
40H. Interrupt registers, stack pointer, Timer 0, UART, P3.0 and
P3.1 must be in the reset state. EA and PSEN must not be affected.
A reset is needed to restart the user program after programming.
The following baudrates will be detected automatically within the
specified C clock range in MHz.
NOTE:
Note that the boot routines can (re) program any number of bytes
from 1 byte to 32 Kbytes, independent in which order or at which
location, but if the security feature is activated, a full erase is
performed and all not programmed bytes become FFH.
Value outside the specified clock range
“ . ”
“ X ”
“ Y ”
“ Z ”
“ R ”
“ V ”
P3.0/RxD
Baudrate
P3.1/TxD
19200
1200
2400
4800
9600
PSEN
ALE
EW
EA
After each record type TT = 00H indication in the
HEX file.
Checksum error of a record in the HEX file
detected.
Wrong record type received
Buffer overflow error (Check Xon/Xoff of terminal)
Verification error (of last written byte)
End record received and programming of
FEEPROM was successful
3K3
f
CLK
1
15.7
1
2
7.9
4
(min)
1)
1)
interface
output of ALE pulses
RS232
Product specification
f
CLK
29.5
59
14.7
3.6
7.3
(max)
1)
1)