MC812A4CPVE8 Freescale Semiconductor, MC812A4CPVE8 Datasheet - Page 81

• 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

CS3 can be used with a 1-Kbyte space in systems not using memory expansion. However, it must be
made to appear as if memory expansion is in use. One of many possible configurations is:
8.2.2 Chip-Selects Used in Conjunction with Memory Expansion
Memory expansion and chip-select functions can work independently, but systems requiring memory
expansion perform better when chip-selects are also used. For each memory expansion window there is
a chip-select (or two) designed to function with it.
Figure 8-2
shows the register settings that correspond to the example. The program space consists of 128 Kbytes
of addressable memory in eight 16-Kbyte pages. Page 7 is always accessible in the space from $C000
to $FFFF. The data space consists of 64 Kbytes of addressable memory in 16, 4-Kbyte pages. Unless
CSD is used to select the external RAM, pages 0 through 6 appear in the $0000 to $6FFF space wherever
there is no higher priority resource. The extra space consists of four, 1-Kbyte pages making 4 Kbytes of
addressable memory.
If memory is increased to the maximum in this example, the program space will consist of 4 Mbytes of
addressable space with 256 16-Kbyte pages and page $FF always available. The data space will be 1
Mbyte of addressable space with 256 4-Kbyte pages and pages $F0 to $F6 mirrored to the $0000 to
$6FFF space. The extra space will be 256 Kbytes of addressable space in 256 1-Kbyte pages.
Freescale Semiconductor
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Select the desired 1-Kbyte space for EPAGE (EWDIR in MISC in the MMI).
Write the EPAGE register with $0000, if EWDIR is one or $0001 if EWDIR is 0.
Designate all port G pins as I/O.
Enable EPAGE and CS3.
Make CS3 follow EPAGE.
shows a memory expansion and chip-select example using three chip-selects.
MC68HC812A4 Data Sheet, Rev. 7
Generation of Chip-Selects
Table 8-3
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