PSD834F3A-15MT View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

PSD834F3A-15MT

Flash in-system programmable (ISP) ipherals for 8-bit MCUs, 5 V

STMicroelectronics 

Programming Flash memory

PSD8XXFX

any location within the sector being erased to get the Toggle flag bit (DQ6) and the Error flag

bit (DQ5).

PSDsoft Express generates ANSI C code functions which implement these Data Toggling

algorithms.

8.3

Unlock Bypass (PSD833F2x, PSD834F2x, PSD853F2x,

PSD854F2x)

The Unlock Bypass instructions allow the system to program bytes to the Flash memories

faster than using the standard Program instruction. The Unlock Bypass mode is entered by

first initiating two Unlock cycles. This is followed by a third WRITE cycle containing the

Unlock Bypass code, 20h (as shown in Table 10).

t(s) The Flash memory then enters the Unlock Bypass mode. A two-cycle Unlock Bypass

Program instruction is all that is required to program in this mode. The first cycle in this

c instruction contains the Unlock Bypass Program code, A0h. The second cycle contains the

du program address and data. Additional data is programmed in the same manner. These

ro instructions dispense with the initial two Unlock cycles required in the standard Program

instruction, resulting in faster total Flash memory programming.

te P During the Unlock Bypass mode, only the Unlock Bypass Program and Unlock Bypass

Reset Flash instructions are valid.

ole To exit the Unlock Bypass mode, the system must issue the two-cycle Unlock Bypass Reset

s Flash instruction. The first cycle must contain the data 90h; the second cycle the data 00h.

Obsolete Product(s) - Ob Addresses are Don’t Care for both cycles. The Flash memory then returns to READ mode.

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Doc ID 7833 Rev 7

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