After lot of trouble, I reduced my code to following and tested in silabs IDE. Still It shows Flash error. This small program tries to erase sector 0x1000 and tries to write at 0x1030 location.

Initialisation code is derived from Configutor from Silab.

Program was tested in single stepping and free run, with same result.

I have screen shot of event, but I do not know how to post.

Vimal Amin

$include (C:\Keil\C51\ASM\C8051F350.INC)
cseg at 00
Start:
Mov VDM0CN,0x80; Enable vcc monitor
Mov Dptr,#0
Loop: Djnz Dpl,$
Djnz Dph,Loop;

Mov PCA0MD,#~040H; Disable PCA and watchdog
Mov PCA0MD,#0
Mov OSCICN,#0x83; Enable Internal Osc. with devider = 8
Mov PCA0CPM0,#0; Disable comparators
Mov PCA0CPM1,#0
Mov PFE0CN,#0; Prefatch disabled

Mov Dptr,#01030H

Mov PSCTL,#3; // PSWE = 1, PWEE = 1
Mov FLKEY,0xA5; // Key Sequence 1
Mov FLKEY,0xF1; // Key Sequence 2
Mov A,#0
Movx @Dptr,A // Erase
Mov PSCTL,#0x00; // PSWE = 0 disable write to Flash

Mov PSCTL,#1; // PSWE = 1
Mov FLKEY,0xA5; // Key Sequence 1
Mov FLKEY,0xF1; // Key Sequence 2
Mov A,#07
Movx @Dptr,A

Mov PSCTL,#0x00; // PSWE = 0 disable write to Flash
Sjmp $
end