MC812A4CPVE8 Freescale Semiconductor, MC812A4CPVE8 Datasheet - Page 80

• Manufacturer Part Number: MC812A4CPVE8
• Description: IC MCU 16BIT EEPROM 4K 112-LQFP
• Manufacturer: Freescale Semiconductor
• Series: HC12r

Specifications of MC812A4CPVE8

• Core Processor: CPU12
• Core Size: 16-Bit
• Speed: 8MHz
• Connectivity: SCI, SPI
• Peripherals: POR, WDT
• Number Of I /o: 83
• Program Memory Size: 4KB (4K x 8)
• Program Memory Type: EEPROM
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 8x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 112-LQFP
• Processor Series: HC812A
• Core: HC12
• Data Bus Width: 16 bit
• Data Ram Size: 1 KB
• Interface Type: SCI, SPI
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 91
• Number Of Timers: 8
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit, 8 Channel
• Controller Family/series: 68HC12
• No. Of I/o's: 91
• Eeprom Memory Size: 4KB
• Ram Memory Size: 1KB
• Cpu Speed: 8MHz
• No. Of Timers: 1
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

Memory Expansion and Chip-Select
8.2 Generation of Chip-Selects
To use chip-selects the MCU must be in one of the expanded modes. Each of the seven chip-selects has
an address space for which it is active — that is, when the current CPU address is in the range of that
chip-select, it becomes active. Chip-selects are generally used to reduce or eliminate external address
decode logic. These active low signals usually are connected directly to the chip-select pin of an external
device.
8.2.1 Chip-Selects Independent of Memory Expansion
Three types of chip-selects are program memory chip-selects, other memory chip-selects and peripheral
chip-selects. Memory chip-selects cover a medium-to-large address space. Peripheral chip-selects
(CS3–CS0) cover a small address space. The program memory chip-select includes the vector space and
is generally used with non-volatile memory. To start the user’s program, the program chip-select is
designed to be active out of reset. This is the only chip-select which has a functional difference from the
others, so a small memory could use a peripheral chip-select and a peripheral could use a memory
chip-select.
Figure 8-1
the register settings that correspond to the example. Chip-selects CS2–CS0 always map to the same
2-Kbyte block as the internal register space. The internal registers cover the first 512 bytes and these
chip-selects cover all or part of the 512 bytes following the register space blocking out a full 1-Kbyte
space. CS3 can map with these other chip-selects or be used in a 1-Kbyte space by itself which starts at
either $0000 or $0400. CS3 can be used only for a 1-Kbyte space when it selects the E page of memory
expansion and E page is active.
80
$0800–$6FFF
$7000–$7FFF
DWEN = 1
$7000–$7FFF
DWEN = 0
$8000–$BFFF
PWEN = 1
$8000–$BFFF
PWEN = 0
$C000–$FFFF
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).
Address
Internal
shows peripheral chip-selects in an expanded portion of the memory map.
PPA21 PPA20 PPA19 PPA18 PPA17 PPA16 PPA15 PPA14
A21
1
1
1
1
1
Table 8-1. Memory Expansion Values
A20
1
1
1
1
1
PDA19 PDA18 PDA17 PDA16 PDA15 PDA14 PDA13 PDA12
A19
1
1
1
1
MC68HC812A4 Data Sheet, Rev. 7
A18
1
1
1
1
A17
1
1
1
1
A16
1
1
1
1
A15
A15
A15
A15
A15
(1)
(Continued)
A14
A14
A14
A14
A14
A13
A13
A13
A13
A13
A13
Freescale Semiconductor
A12
A12
A12
A12
A12
A12
Table 8-2
A11
A11
A11
A11
A11
A11
A11
shows
A10
A10
A10
A10
A10
A10
A10