ST ST10F276E, User Manual, Page: 512 / 564

Power reduction modes UM0404
512/564 DocID13284 Rev 2
(WR), or to a defined state which is based on the last bus access (BHE). Port pins which are
used as external address/data bus hold the address/data which was output during the last
external memory access before entry into Idle mode under the following conditions:
P0H outputs the high byte of the last address if a multiplexed bus mode with 8-bit data bus
is used, otherwise P0H is floating. P0L is always floating in Idle mode.
PORT1 outputs the lower 16 bits of the last address if a de-multiplexed bus mode is used,
otherwise the output pins of PORT1 represent the port latch data.
Port4 outputs the segment address for the last access on those pins that were selected
during reset, otherwise the output pins of Port4 represent the port latch data.
During power down mode the oscillator and the clocks to the CPU and to the peripherals
are turned off. Like in Idle mode, all port pins which are configured as general purpose
output pins output the last data value which was written to their port output latches.
When the alternate output function of a port pin is used by a peripheral the state of this pin is
determined by the last action of the peripheral before the clocks were switched off.
The Table 67 summarizes the state of all ST10F276 output pins during Idle and Power
Down mode.
Table 67. Output pin state during Idle and power down modes
ST10F276
output pin(s)
Idle mode Power Down Mode
No
external bus
External bus
enabled
No
external bus
External bus
enabled
ALE Low Low Low Low
RD, WR High High High High
CLKOUT Active Active High High
RSTOUT 1 1 1 1
P0L Port Latch Data Floating Port Latch Data Floating
P0H Port Latch Data A15...A8
2
/ Float Port Latch Data A15...A8
2
/ Float
PORT1 Port Latch Data
Last Address
3
/
Port Latch Data
Port Latch Data
Last Address
3
/
Port Latch Data
Port4 Port Latch Data
Port Latch
Data/Last segment
Port Latch Data
Port Latch
Data/Last segment
BHE Port Latch Data Last value Port Latch Data Last value
HLDA Port Latch Data Last value Port Latch Data Last value
BREQ Port Latch Data High Port Latch Data High
CSx Port Latch Data Last value
4
Port Latch Data Last value
4
Other Port
Output Pins Port Latch Data /
Alternate Function Port Latch Data /
Alternate Function Port Latch Data /
Alternate Function Port Latch Data /
Alternate Function