MC68HC812A4 Datasheet, PDF (123/342 Pages) Motorola, Inc – 16-bit device composed of standard on-chip peripheral modules connected by an intermodule bus. Modules include

Memory Expansion and Chip-Select
Introduction
Table 8-1. Memory Expansion Values⁽¹⁾
Internal
Address
A21 A20 A19 A18 A17 A16 A15 A14 A13 A12 A11 A10
$0000–$03FF
EWDIR⁽²⁾= 1,
1
1
1
1 PEA17 PEA16 PEA15 PEA14 PEA13 PEA12 PEA11 PEA10
EWEN = 1
$0000–$03FF
EWDIR
or
1
1
1
1
1
1
A15 A14 A13 A12 A11 A10
EWEN = 0
$0400–$07FF
EWDIR = 0,
1
1
1
1 PEA17 PEA16 PEA15 PEA14 PEA13 PEA12 PEA11 PEA10
EWEN = 1
$0400–$07FF
EWDIR = 1,
EWEN = x
or
1
1
1
1
1
1
A15 A14 A13 A12 A11 A10
EWDIR = x,
EWEN = 0
$0800–$6FFF
1
1
1
1
1
1
A15 A14 A13 A12 A11 A10
$7000–$7FFF
DWEN = 1
1
1 PDA19 PDA18 PDA17 PDA16 PDA15 PDA14 PDA13 PDA12 A11 A10
$7000–$7FFF
DWEN = 0
1
1
1
1
1
1
A15 A14 A13 A12 A11 A10
$8000–$BFFF
PWEN = 1
PPA21 PPA20 PPA19 PPA18 PPA17 PPA16 PPA15 PPA14 A13
A12
A11
A10
$8000–$BFFF
PWEN = 0
1
1
1
1
1
1
A15 A14 A13 A12 A11 A10
$C000–$FFFF
1
1
1
1
1
1
A15 A14 A13 A12 A11 A10
1. All port G assigned to memory expansion
2. The EWDIR bit in the MISC register selects the E window address (1 = $0000–$03FF including direct space and
0 = $0400–$07FF).
Advance Information
MOTOROLA
Memory Expansion and Chip-Select
MC68HC812A4 — Rev. 3.0
123