Philips Semiconductors
Preliminary data
P89C51RB2/P89C51RC2/
P89C51RD2
80C51 8-bit Flash microcontroller family
16KB/32KB/64KB ISP/IAP Flash with 512B/512B/1KB RAM
2001 Jun 27
46
In Application Programming Method
Several In Application Programming (IAP) calls are available for use by
an application program to permit selective erasing and programming of
Flash sectors. All calls are made through a common interface,
PGM_MTP. The programming functions are selected by setting up
the microcontroller’s registers before making a call to PGM_MTP at
FFF0H. The oscillator frequency is an integer number rounded down
to the nearest megahertz. For example, set R0 to 11 for 11.0592 MHz.
Results are returned in the registers. The IAP calls are shown in
Table 9.
Using the Watchdog Timer (WDT)
The 89C51Rx2 devices support the use of the WDT in IAP. The user
specifies that the WDT is to be fed by setting the most significant bit
of the function parameter passed in R1 prior to calling PGM_MTP.
The WDT function is only supported for Block Erase when using
Quick Block Erase. The Quick Block Erase is specified by
performing a Block Erase with register R0 = 0. Requesting a WDT
feed during IAP should only be performed in applications that use
the WDT since the process of feeding the WDT will start the WDT if
the WDT was not running.
Table 9.
IAP calls
IAP CALL
PARAMETER
PROGRAM DATA BYTE
Input Parameters:
R0 = osc freq (integer)
R1 = 02h
R1 = 82h (WDT feed)
DPTR = address of byte to program
ACC = byte to program
Return Parameter
ACC = 00 if pass, !00 if fail
ERASE BLOCK
Input Parameters:
R0 = osc freq (integer)
R0 = 0 (Quick Erase)
R1 = 01h
R1 = 81h (WDT feed)
DPH = block code as shown below:
block 0,
0k to
8k, 00H
block 1,
8k to 16k, 20H
block 2, 16k to 32k, 40H
block 3, 32k to 48k, 80H
block 4, 48k to 64k, C0H
DPL = 00h
Return Parameter
none
ERASE BOOT VECTOR
Input Parameters:
R0 = osc freq (integer)
R1 = 04h
R1 = 84h (WDT feed)
DPH = 00h
DPL = don’t care
Return Parameter
none
PROGRAM SECURITY BIT
Input Parameters:
R0 = osc freq (integer)
R1 = 05h
R1 = 85h (WDT feed)
DPH = 00h
DPL = 00h – security bit # 1 (inhibit writing to Flash)
01h – security bit # 2 (inhibit Flash verify)
02h – security bit # 3 (disable external memory)
Return Parameter
none
PROGRAM STATUS BYTE
Input Parameters:
R0 = osc freq (integer)
R1 = 06h
R1 = 86h (WDT feed)
DPH = 00h
DPL = 00h – program status byte
ACC = status byte
Return Parameter
ACC = status byte