Flash Electronically Erasable Programmable Memory (Flash Eeprom); Electrically Erasable Programmable Memory (Eeprom) - Motorola GM-950 Manual

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2.13 FLASH Electronically Erasable Programmable Memory
(FLASH EEPROM)
The 256 KByte FLASH EEPROM (U0102) contains the radio operating software. This software is
common to all open architecture radios within a given model type. This is, as opposed to the
codeplug information stored in EEPROM (U0104) which could be different from one user to another
in the same company.
In normal operating mode, this memory is only read, not written to. The memory access signals (CE,
OE and WE) are generated by the µP.
To upgrade/reprogram the FLASH software, the µP must be set in bootstrap operating mode, and
the FLASH device pin (U0102-9) V
account, the voltage at J400-12 to enable FLASH programming may range between 12.1 and 13.1V.
This voltage also switches Q0102 on and in turn Q0103 off. The low state at collector of Q0102 pulls
MODA LIR (U0101-77) and MODB VSTBY (U0101-76) via diode D0101 to low which enables the
bootstrap operating mode after power up. The high state at collector of Q0103 enables the µP to
control the FLASH EN OE (U0102-32) input via U0106-4. Chip select (U102-30) and read or write
operation (U102-7) are controlled by µP pins 29 and 33. In normal operating mode V
which switches Q0102 off and Q0103 on.
Resistor divider pair R0132 and R0133 set up 4.1 V on U0102-9 which reduces the chance of logic
transitions. The FLASH device may be reprogrammed 1,000 times without issue. It is not
recommended to reprogram the FLASH device at a temperature below 0°C.
Capacitor C0131 serves to filter out any AC noise which may ride on +5V at U0101, and C0132
filters out any AC noise on V
2.14

Electrically Erasable Programmable Memory (EEPROM)

The optional EEPROM (U0104 or U0107) contains additional radio operating parameters such as
operating frequency and signalling features, commonly known as the codeplug. It is also used to
store radio operating state parameters such as current mode and volume. U0104 can have up to
8Kbyte and U0107 up to 16 Kbyte. This memory can be written to in excess of 100,000 times and
will retain the data when power is removed from the radio. The memory access signals (SI, SO and
SCK) are generated by the µP and chip select (CS) is generated by address decoder U0105-4.
Additional EEPROM is contained in the µP (U0101). This EEPROM is used to store radio tuning and
alignment data. Like the external EEPROM this memory can be programmed multiple times and will
retain the data when power is removed from the radio.
Note: The external EEPROM plus the 640 bytes of internal EEPROM in the 68HC11K1 comprise
the complete codeplug.
5C.3-8
must be between 11.4 and 12.6 V. Taking diode D0102 into
pp
.
pp
is below 5V
PP
Theory of Operation