Nokia RH-9 Series Ccs Technical Documentation page 62

RH-9
System Module & UI
When the MCU boots it looks for flash programming indication on the MBUS_RX signal.
If this signal is pulled low the MCU sets up the UART (Universal Asynchronous Receive-
Transfer) module in synchronous mode and uses the FBUS_TX signal to indicate to the
flash prommer that it is ready to accept the secondary download code. All flash pro-
gramming software is downloaded to the UPP internal MCU SRAM.
The MCU also ends up in flash programming mode if the flash is empty, indicated by FFH
in the first memory location in the flash.
Flash Identifiers
The flash has a manufacturer and device identifier for electrical identification. This infor-
mation is used by the flash programming equipment to create the flash identifier for
identifying which device is mounted on the board and correctly setup the EEPROM emu-
lation.
The flash identifier indicates to the MCU, the hardware environment it is working in, in
terms of the number of flashes as well the type, block-size, and configuration of each.
The flash identifier is necessary because DCT4 supports many different flash manufactur-
ers. The flash identifier consists of five words as described below:
The flash identifier is stored in the MCU code space. The MCU code space in the memory
starts at either 80000H or 100000H depending upon the size of the MCU software.
First Word
This word contains information about the number of flash devices connected to the UPP.
It is possible to setup the UPP to support two devices. The MSB indicates the number of
flashes used by the baseband. The number of WAIT states for the random access is spec-
ified over the next 3 bits in this word. The number of WAIT states is specified relative to
the system clock used. The MCU PLL factor (specifying the MCU CLK frequency as a mul-
tiple of system CLK) is specified in the next 2 bits and whether the flash has Read-While-
Write (RWW) capabilities is specified on the LSB.
Second Word
This work contains information about flash sectors available for EEPROM emulation. If
no RWW capability is indicated in the first word, this field then contains information
about the serial EEPROM that is used in the system. The flashes used in RH-9 all have
RWW capability.
Third Word
This word contains similar information as the first word, but the information is about the
second flash if such is used.
Fourth Word
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CCS Technical Documentation
Issue 1 11/02