UM10147_2
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 02 — 28 April 2008
122 of 134
NXP Semiconductors
UM10147
P89LPC952/954 User manual
17.17 User configuration bytes
A number of user-configurable features of the P89LPC952/954 must be defined at
power-up and therefore cannot be set by the program after start of execution. These
features are configured through the use of an Flash byte UCFG1 shown in
Read Sector CRC
Input parameters:
ACC = 05h
R7= sector address
Return parameter(s):
R4= CRC bits 31:24
R5= CRC bits 23:16
R6= CRC bits 15:8
R7= CRC bits 7:0 (if no error)
R7= error status (if error)
Carry= set on error, clear on no error
Read Global CRC
Input parameters:
ACC = 06h
Return parameter(s):
R4= CRC bits 31:24
R5= CRC bits 23:16
R6= CRC bits 15:8
R7= CRC bits 7:0 (if no error)
R7= error status (if error)
Carry= set on error, clear on no error
Read User Code
Input parameters:
ACC = 07h
R4= address (MSB)
R5= address (LSB)
Return parameter(s):
R7= data
Table 104. IAP function calls
…continued
IAP function
IAP call parameters
Table 105. Flash User Configuration Byte 1 (UCFG1) bit allocation
Bit
7
6
5
4
3
2
1
0
Symbol
WDTE
RPE
BOE
WDSE
CLKDBL
FOSC2
FOSC1
FOSC0
Unprogrammed
value
0
1
0
0
0
0
1
1
Table 106. Flash User Configuration Byte 1 (UCFG1) bit description
Bit Symbol
Description
0
FOSC0
CPU oscillator type select. See
for additional information. Combinations other than those
shown in
are reserved for future use should not be used.
1
FOSC1
2
FOSC2
3
CLKDBL Clock doubler. When set, doubles the output frequency of the internal RC oscillator.