Nokia RH-9 Series Ccs Technical Documentation page 61

RH-9
CCS Technical Documentation System Module & UI
tional line), FBUS_TX, and FBUS_RX all located on the ACCDIF[2:0]. The programming
interface connections between the UEM and the UPP constitute the MBUS_TX,
MBUS_RX, FBUS_TX, and FBUS_RX lines, all located on the IACCDIF[5:0]. The interface
also uses the BSI (Battery_Size_Indicator) and the PURX signal connections for the con-
nections between the UEM and the UPP.
Baseband Power Up
The baseband power is controlled by the programming jig in production, and the flash
prommer (via the flashing battery) in reprogramming situations. Reprogramming uses
the flashing battery to apply a supply voltage to the battery terminals and power up the
baseband. The battery and supply voltage generated by the flash prommer interface
equipment should not exceed 4.2 V.
Flash Programming Indication
Flash programming is indicated to the UPP using the MBUS_RX signal between UPP and
UEM. The flash prommer keeps the MBUS line low during UPP boot to indicate that the
flash prommer is connected and flag reprogramming condition to disable the UEM
watchdog. If the UPP MBUS_RX signal is low the MCU enters flash programming mode.
In order to avoid accidental entry to the flash programming mode, the MCU only waits
for a specified time to get input data from the flash prommer. If the timer expires with-
out any data being received, the MCU will continue the boot sequence. The MBUS signal
from the UEM to the flash prommer is used as a clock for the synchronous communica-
tion and the MBUS_RX signal supplies the flash programming clock to the UPP. During
flashing, the phone cannot be booted using conventional power down and power up on
the battery line.
The flash prommer indicates the flash programming to the UEM by writing an 8-bit pass-
word to the UEM. The data is transmitted on the FBUS_RX line and the UEM clocks the
data into a shift register. When the 8-bits have been shifted in the register, the flash
prommer generates a falling edge on the BSI line. This loads the shift register contents in
the UEM into a compare register. If the contents of the compare register match the
default value preset in the UEM, the flash prommer will again pull the MBUS signal to
the UEM low in order to indicate to the MCU that the flash prommer is connected. The
UEM reset state machine performs a reset to the system by keeping PURX low for 10-100
ms. The UEM flash programming mode is valid until the MCU sets a bit in the UEM regis-
ter that indicates the end of the flash programming. Setting this bit also clears the com-
pare register in the UEM previously loaded at the falling edge of the BSI signal. Setting
this bit also enables and resets the UEM watchdog timer to its default value and causes
the UEM to generate a reset to the UPP.
In order to avoid spurious loading of the compare register, the BSI signal is gated during
the UEM master reset and when PURX is low. The BSI signal should not change state in
normal operation unless the battery is removed in which case the BSI signal will be
pulled high.
MCU Boot
Issue 1 11/02 ãNokia Corporation Page 61