PSD835G2V_07 datasheet(44/118 Pages) STMICROELECTRONICS

Part #	PSD835G2V

Description	Flash PSD, 3 V supply, for 8-bit MCUs 4 Mbit 256 Kbit dual Flash memories and 64 Kbit SRAM

PDF	118 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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SRAM

PSD835G2V

44/118

SRAM

The SRAM is enabled when SRAM Select (RS0) from the DPLD is High. SRAM Select

(RS0) can contain up to three 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 (VSTBY, PE6). If you have an external battery connected to

the PSD, the contents of the SRAM are retained in the event of a power loss. The contents

of the SRAM are retained 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.

PE7 can be configured as an output that indicates when power is being drawn from the

external battery. Battery-on Indicator (VBATON, PE7) is High when the supply voltage falls

below the battery voltage and the battery on Voltage Stand-by (VSTBY, PE6) is supplying

power to the internal SRAM.

SRAM Select (RS0), Voltage Stand-by (VSTBY, PC2) and Battery-on Indicator (VBATON,

PC4) are all configured using PSDsoft Express Configuration.

The SRAM Select (RS0), VBATON and VSTBY are all configured using PSDsoft.

PSD835G2V Datasheet(PDF) 44 Page - STMicroelectronics