UM10310_1 © NXP B.V. 2008. All rights reserved.
User manual Rev. 01 — 1 December 2008 122 of 139
NXP Semiconductors UM10310
P89LPC9321 User manual
18.12 In-application programming (IAP)
Several In-Application Programming (IAP) calls are available for use by an application
program to permit selective erasing and programming of Flash sectors, pages, security
bits, configuration bytes, and device id. 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 FF03H. The IAP calls are shown in
Table110.
18.13 IAP authorization key
IAP functions which write or erase code memory require an authorization key be set by
the calling routine prior to performing the IAP function call. This authorization key is set by
writing 96H to RAM location FFH. The following example was written using the Keil C
compiler. The methods used to access a specific physical address in memory may vary
with other compilers.
#include <ABSACC.H> /* enable absolute memory access */
#define key DBYTE[0xFF] /* force key to be at address 0xFF */
short (*pgm_mtp) (void) = 0xFF00; /* set pointer to IAP entry point */;
key = 0x96; /* set the authorization key */
pgm_mtp (); /* execute the IAP function call */
After the function call is processed by the IAP routine, the authorization key will be
cleared. Thus it is necessary for the authorization key to be set prior to EACH call to
PGM_MTP that requires a key. If an IAP routine that requires an authorization key is
called without a valid authorization key present, the MCU will perform a reset.
18.14 Flash write enable
This device has hardware write enable protection. This protection applies to both ISP and
IAP modes and applies to both the user code memory space and the user configuration
bytes (UCFG1, UCFG2, BOOTVEC, and BOOTSTAT). This protection does not apply to
ICP or parallel programmer modes. If the Activate Write Enable (AWE) bit in BOOTSTA T.7
06 Read Global CRC
: 00xxxx06cc
Where: xxxx = required field but value is a ‘don’t care’; cc= checksum
Example: 00000006FA
07 Direct Load of Baud Rate
: 02xxxx07HHLLcc
Where: xxxx = required field but value is a ‘don’t care’; HH= high byte of timer;
LL = low byte of timer; cc = checksum
Example: 02000007FFFFF9
08 Reset MCU
: 00xxxx08cc
Where: xxxx = required field but value is a ‘don’t care’; cc = checksum
Example: 00000008F8
Table 108. In-system Programming (ISP) hex record formats …continued
Record type Command/data function