Phytec phyCORE-MCF548x, Руководство по оборудованию

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System Memory
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PHYTEC Messtechnik GmbH 2005 L-645e_1
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6.3 Serial Memory
The phyCORE-MCF548x features a non-volatile memory device with
a serial I
2
C interface. This memory can be used for storage of
configuration data or operating parameters, that must not be lost in the
event of a power interruption. Depending on the module’s
configuration, this memory can be in the form of an EEPROM, FRAM
or SRAM. The available capacity ranges from 512 Byte to 32 kByte.
If SRAM is used, solder jumper J7 must be closed at position 2+3 to
supply the memory device via VPD, hence supporting battery backup.
The MCF548X provides an on-chip I
2
C interface to which the
memory device is connected.
Table 7 gives an overview of the possible devices for use at U15 as of
the printing of this manual.
Type Size I
2
C
Frequency
Address
Pins Write
Cycles Life of
Data Device Manufacturer
256/512
Byte 400 kHz A2, A1, A0 1 000 000 100 yrs. CAT24WC02/04 CATALYST
1/ 2 kByte 400 kHz A2, A1, A0 1 000 000 100 yrs. CAT24WC08/16 CATALYST
4/8 kByte 400 kHz A2, A1, A0 1 000 000 100 yrs. CAT24WC32/64 CATALYST
EEPROM
32 kByte 1 MHz A1, A0 100 000 100 yrs. CAT24WC256 CATALYST
512 Byte 1 MHz A2, A1 10 billion 10 yrs. FM24C04 RAMTRON FRAM
8 kByte 1 MHz A2, A1, A0 10 billion 10 yrs. FM24C64 RAMTRON
SRAM 256 Byte 100 kHz A2, A1, A0 - - PCF8570 PHILIPS
Table 7: Serial Memory Options for U15
It is important to note that the RTC U16 is also connected to the I
2
C
bus. The RTC can operate with a bus frequency up to 400 kHz.
Therefore the use of high bus frequencies for accessing the serial
memory is not recommended. The RTC has the I
2
C bus slave address
0xA2 / 0xA3. The slave address of the serial memory must be selected
accordingly using the solder jumpers J23 (A1) and J24 (A2), so that
no collision occurs. The address input A0 is hard-wired to GND.