Freescale Semiconductor M68HC12A4EVB, Руководство пользователя

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User’s Manual M68HC12A4EVB Evaluation Board — Rev. 1
88 Hardware Reference MOTOROLA
Hardware Reference
4.7.2 Chip Selects
Header W11 connects an MCU chip select signal to memory devices in the
ROM (U7, U9A, U9B) and RAM (U4, U6A, U6B) sockets. Pins in columns 1
and 2 determine the chip select used for memory devices in ROM sockets. Pins
in columns 2 and 3 determine the chip select used for memory devices in RAM
sockets.
Figure 4-2 shows the W11 jumper settings for the factory-default memory
configuration. The illustration demonstrates the correct settings for CSP0 to
serve as the ROM chip select and CSD to serve as the RAM chip select.
Figure 4-2. Chip Select Header
Table 4-3. EVB Memories Supplied
Type EPROM SRAM
Manufacturer Atmel Corporation
Dallas Semiconductor
Corporation
Part number AT27LV256R-20PC DS2064
Size 256 Kbits (32 K x 8) 64 Kbits (8 K x 8 bits)
Package width 600 mil 600 mil
Pin count 28 pin 28 pin
Power supply +3.0 to +5.5 Vdc +2.7 to +5.5 Vdc
Access times 200 ns 150 ns @ 5 V, 300 ns @ 3 V
Wait states required
(E-clock stretches)
1 1
3 2 1
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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