Datasheet

Chapter 4 Memory Map and Register Definition
MC9S08QG8 and MC9S08QG4 Data Sheet, Rev. 5
Freescale Semiconductor 41
4.3 Register Addresses and Bit Assignments
The registers in the MC9S08QG8/4 are divided into these groups:
• Direct-page registers are located in the first 96 locations in the memory map; these are accessible
with efficient direct addressing mode instructions.
• High-page registers are used much less often, so they are located from 0x1800 and above in the
memory map. This leaves more room in the direct page for more frequently used registers and
RAM.
• The nonvolatile register area consists of a block of 16 locations in FLASH memory at
0xFFB0–0xFFBF. Nonvolatile register locations include:
— NVPROT and NVOPT are loaded into working registers at reset.
— An 8-byte backdoor comparison key that optionally allows a user to gain controlled access to
secure memory.
Because the nonvolatile register locations are FLASH memory, they must be erased and
programmed like other FLASH memory locations.
Direct-page registers can be accessed with efficient direct addressing mode instructions. Bit manipulation
instructions can be used to access any bit in any direct-page register. Table 4-2 is a summary of all
user-accessible direct-page registers and control bits.
The direct page registers in Table 4-2 can use the more efficient direct addressing mode that requires only
the lower byte of the address. Because of this, the lower byte of the address in column one is shown in bold
text. In Table 4-3 and Table 4-4, the whole address in column one is shown in bold. In Table 4-2, Table 4-3,
and Table 4-4, the register names in column two are shown in bold to set them apart from the bit names to
the right. Cells that are not associated with named bits are shaded. A shaded cell with a 0 indicates this
unused bit always reads as a 0. Shaded cells with dashes indicate unused or reserved bit locations that could
read as 1s or 0s.
Table 4-2. Direct-Page Register Summary
AddressRegister NameBit 7654321Bit 0
0x0000 PTAD 0 0 PTAD5 PTAD4 PTAD3 PTAD2 PTAD1 PTAD0
0x0001 PTADD
0 0 PTADD5 PTADD4 PTADD3 PTADD2 PTADD1 PTADD0
0x0002 PTBD PTBD7 PTBD6 PTBD5 PTBD4 PTBD3 PTBD2 PTBD1 PTBD0
0x0003 PTBDD PTBDD7 PTBDD6 PTBDD5 PTBDD4 PTBDD3 PTBDD2 PTBDD1 PTBDD0
0x0004–
0x000B
Reserved
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
0x000C KBISC
0 0 0 0 KBF KBACK KBIE KBMOD
0x000D KBIPE KBIPE7 KBIPE6 KBIPE5 KBIPE4 KBIPE3 KBIPE2 KBIPE1 KBIPE0
0x000E KBIES KBEDG7 KBEDG6 KBEDG5 KBEDG4 KBEDG3 KBEDG2 KBEDG1 KBEDG0
0x000F IRQSC
0IRQPDD0 IRQPE IRQF IRQACK IRQIE IRQMOD
0x0010 ADCSC1 COCO AIEN ADCO ADCH
0x0011 ADCSC2 ADACT ADTRG ACFE ACFGT
— — — —
0x0012 ADCRH
0 0 0 0 0 0 ADR9 ADR8
0x0013 ADCRL ADR7 ADR6 ADR5 ADR4 ADR3 ADR2 ADR1 ADR0