NuMicro™ Mini51 Technical Reference ManualFeb 9, 2012 Page 125 of 342 Revision V1.03NUMICRO™ MINI51 TECHNICAL REFERENCE MANUAL5.7.4.2 Boot SelectionThe NuMicro Mini51TM provides in system programming (ISP) feature for user to update programmemory when chip is mounted on PCB. A dedicated 2KB program memory is used to store ISPfirmware. User can select to start program fetch from APROM or LDROM by (CBS) in Config0.There are two kinds of mapping for booting selection.Table 5.7-2 Boot Selection TableCBS Boot Selection1 CPU booting from APROM, flash access range including APROM and Data Flash;LDROM cannot be accessed directly, except through ISP.APROM is write-protected in this mode.0 CPU booting from LDROM, flash access range only LDROM 2KB; APROM cannot beaccessed directly, except through ISP.APROM can be updated in this mode.5.7.4.3 Data FlashThe NuMicro Mini51TM provides data flash for user to store data which is read/written through theISP procedure. The size of each erase unit is 512 bytes. When a word will be changed, all 128words need to be copied to another page or SRAM in advance. The data flash base address isdefined by DFBA if DFEN bit in Config0 is enabled. For example, for 4K/2K/1K/0KB data flash, theDFBA setting value is listed in the following table.Table 5.7-3 Data Flash TableData Flash 4KB(DFEN=0)2KB(DFEN=0)1KB(DFEN=0)0KB(DFEN=1)16K Flash DFBA=0x0000_3000 DFBA=0x0000_3800 DFBA=0x0000_3C00 DFEN=18K Flash DFBA=0x0000_1000 DFBA=0x0000_1800 DFBA=0x0000_1C00 DFEN=14K Flash Forbidden DFBA=0x0000_0800 DFBA=0x0000_0C00 DFEN=1
