C51: In-Application Programming (IAP) on Philips LPC9XX

Information in this article applies to:

• C51, all versions

QUESTION

I'm using a Philips P89LPC932 that provides In-system Application Programming (IAP) with an entry address at 0xFF00.

Is there a clever way to access the IAP functions directly from C without the need to write assembler interface routines?

Some Philips LPC900 variants require to set a key value in the idata memory at address 0xFF.

Is it possible to set this key from the C-level?

ANSWER

Yes, there is a clever way. Just add the following code to your application. For devices that require a key value, include the key assignment in your code.

#include                               // SFR header file
#include                                  // Absolute memory address macros

#define IAP_key  DBYTE[0xFF]                        // access macro for key value

unsigned char IAP_ProgramUserCodePage (
                               char idata * ptr,    // Pointer to data buffer in RAM
                           unsigned short   addr,   // Page address
                           unsigned char    nb)  {  // number of bytes to program
  ptr = ptr;                                        // avoid warnings
  addr = addr;
  nb = nb;
  IAP_key = 0x96;                                   // write key value
  ACC = 0;                                          // MOV  A,#00H
  return ((unsigned char (code *)(void)) 0xFF00)(); // LJMP 0FF00H
}

unsigned char IAP_ReadVersionId (void) {
  ACC = 1;                                          // MOV  A,#01H
  return ((unsigned char (code *)(void)) 0xFF00)(); // LJMP 0FF00H
}

unsigned char IAP_MiscWrite (unsigned char regaddr, unsigned char value) {
  regaddr = regaddr;                                // avoid warnings
  value   = value;
  IAP_key = 0x96;                                   // write key value
  ACC = 2;                                          // MOV  A,#02H
  return ((unsigned char (code *)(void)) 0xFF00) ); // LJMP 0FF00H
}

unsigned char IAP_MiscRead (unsigned char regaddr) {
  regaddr = regaddr;                                // avoid warnings
  ACC = 3;                                          // MOV  A,#03H
  return ((unsigned char (code *)(void)) 0xFF00)(); // LJMP 0FF00H
}

unsigned char IAP_EraseSector (unsigned char mode, unsigned short addr) {
  mode = mode;                                      // avoid warnings
  addr = addr;
  IAP_key = 0x96;                                   // write key value
  ACC = 4;                                          // MOV  A,#04H
  return ((unsigned char (code *)(void)) 0xFF00)(); // LJMP 0FF00H
}

unsigned long IAP_ReadSectorCRC (unsigned char sector) {
  sector = sector;                                  // avoid warnings
  ACC = 5;                                          // MOV  A,#05H
  return ((unsigned long (code *)(void)) 0xFF00)(); // LJMP 0FF00H
}

long unsigned IAP_ReadGlobalCRC (void)  {
  ACC = 6;                                          // MOV  A,#06H
  return ((unsigned char (code *)(void)) 0xFF00)(); // LJMP 0FF00H
}

unsigned char IAP_ReadUserCode_ (char dummy, unsigned short addr) {
  dummy = dummy;                                    // avoid warnings
  addr = addr;
  ACC = 7;                                          // MOV  A,#07H
  return ((unsigned char (code *)(void)) 0xFF00)(); // LJMP 0FF00H
}

unsigned char IAP_ReadUserCode (unsigned short addr) {
  return IAP_ReadUserCode_ (0, addr);               // move addr to R4|R5
}

Depending on the CY flag, the return value of these IAP functions is a status or memory value. You can query the CY flag immediately after the IAP function call as follows:

    :
        // program the 'buf' content to address 0x1200
  status = IAP_ProgramUserCodePage (buf, 0x1200, sizeof (buf));
  if (CY)  return (status);     // error occured
    :

MORE INFORMATION

• Philips P89LPC9xx User's Manuals

SEE ALSO

• C51: Interface for IAP Functions on NXP Devices

• GENERAL: Difference Between ISP and IAP

Last Reviewed: Thursday, February 25, 2021