Datasheet

ManualsBrandsNXP SEMICONDUCTORS ManualsMicrocontrollers, Microprocessors & QuartzesEmbedded microcontroller LQFP 112 (20x20) 16-Bit 8 MHz I/O number 83

Generation of Chip-Selects

MC68HC812A4 Data Sheet, Rev. 7

Freescale Semiconductor 83

Figure 8-2. Memory Expansion and Chip-Select Example

Table 8-3. Example Register Settings

WINDEF $E0 Enable EPAGE, DPAGE, PPAGE

MXAR $01

Port G bit 0 assigned as extended address

ADDR16

CSCTL0 %00111xxx Enables CSP0, CSD, and CS3

CSCTL1 $18

Makes CSD follow $0000–$7FFF and CS3

select EPAGE

MISC %0xxxxxxx Puts EPAGE at $0400–$09FF

$0000

$1000

$2000

$3000

$4000

$5000

$6000

$7000

$8000

$9000

$A000

$B000

$C000

$D000

$E000

$F000

$FFFF

$FFC0–$FFFF

PAG E 7

DATA CHIP-SELECT: (CSD)

$0000 TO $7FFF

DATA WINDOW: $7000 to $7FFF

PROGRAM CHIP-SELECT 0: (CSP0)

$8000 TO $FFFF

PROGRAM PAGES: $8000 to $BFFF

PAG E 3

CHIP-SELECT 3: (CS3)

$0400 TO $07FF

EXTERNAL SPACE

INTERNAL SPACE

REGISTERS &

RAM & CS[3:0]

EEPROM

VECTORS

NOTE 2

PAG E xF

NOTE 1: Some 4-Kbyte blocks of phys-

ical external data memory can be se-

lected by an access to $0000–$6FFF in

the 64-Kbyte map or as pages 0

through 6 in the data window. On-chip

registers, EEPROM, and EPAGE have

higher priority than CSD.

NOTE 2: The last page of physical pro-

gram memory can be selected by an

access to $C000–$FFFF in the

64-Kbyte map or as page 7 in the pro-

gram window.

NOTE 1

. . .