psd813f3 STMicroelectronics, psd813f3 Datasheet - Page 29

• Manufacturer Part Number: psd813f3
• Description: Flash In-system Programmable Isp Peripherals For 8-bit Mcus
• Manufacturer: STMicroelectronics

SRAM
The SRAM is enabled when SRAM Select (RS0)
from the DPLD is High. SRAM Select (RS0) can
contain up to two product terms, allowing flexible
memory mapping.
The SRAM can be backed up using an external
battery. The external battery should be connected
to Voltage Stand-by (V
external battery connected to the PSD, the con-
tents of the SRAM are retained in the event of a
power loss. The contents of the SRAM are re-
tained so long as the battery voltage remains at
2 V or greater. If the supply voltage falls below the
battery voltage, an internal power switch-over to
the battery occurs.
STBY
, PC2). If you have an
PSD813F2, PSD833F2, PSD834F2, PSD853F2, PSD854F2
PC4 can be configured as an output that indicates
when power is being drawn from the external bat-
tery. Battery-on Indicator (VBATON, PC4) is High
with the supply voltage falls below the battery volt-
age and the battery on Voltage Stand-by (V
PC2) is supplying power to the internal SRAM.
SRAM Select (RS0), Voltage Stand-by (V
PC2) and Battery-on Indicator (VBATON, PC4)
are all configured using PSDsoft Express Configu-
ration.
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STBY
STBY
,
,