PSD833F3VA-90UT View Datasheet(PDF) - STMicroelectronics
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Description
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PSD833F3VA-90UT Datasheet PDF : 128 Pages
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Programming in-circuit using the JTAG serial interface
PSD8XXFX
Reset (RESET) will prevent or interrupt JTAG operations if the JTAG enable register is used
to enable the JTAG pins.
The PSD supports JTAG In-System-Configuration (ISC) commands, but not Boundary
Scan. The PSDsoft Express software tool and FlashLINK JTAG programming cable
implement the JTAG In-System-Configuration (ISC) commands. A definition of these JTAG
In-System-Configuration (ISC) commands and sequences is defined in a supplemental
document available from ST. This document is needed only as a reference for designers
who use a FlashLINK to program their PSD.
19.2 JTAG extensions
TSTAT and TERR are two JTAG extension signals enabled by an “ISC_ENABLE” command
) received over the four standard JTAG signals (TMS, TCK, TDI, and TDO). They are used to
t(s speed Program and Erase cycles by indicating status on PSD signals instead of having to
scan the status out serially using the standard JTAG channel. See Application Note
uc AN1153.
d TERR indicates if an error has occurred when erasing a sector or programming a byte in
ro Flash memory. This signal goes low (active) when an Error condition occurs, and stays low
P until an “ISC_CLEAR” command is executed or a chip Reset (RESET) pulse is received
te after an “ISC_DISABLE” command.
le TSTAT behaves the same as Ready/Busy described in Section 6.3.1: Ready/Busy (PC3).
o TSTAT is high when the PSD device is in READ mode (primary and secondary Flash
bs memory contents can be read). TSTAT is low when Flash memory program or erase cycles
are in progress, and also when data is being written to the secondary Flash memory.
- O TSTAT and TERR can be configured as open-drain type signals during an “ISC_ENABLE”
) command. This facilitates a wired-OR connection of TSTAT signals from multiple PSD
t(s devices and a wired-OR connection of TERR signals from those same devices. This is
c useful when several PSD devices are “chained” together in a JTAG environment.
Obsolete Produ 19.3
Security and Flash memory protection
When the security bit is set, the device cannot be read on a device programmer or through
the JTAG port. When using the JTAG port, only a Full Chip Erase command is allowed.
All other Program, Erase and Verify commands are blocked. Full Chip Erase returns the part
to a non-secured blank state. The Security bit can be set in PSDsoft Express configuration.
All primary and secondary Flash memory sectors can individually be sector protected
against erasures. The sector protect bits can be set in PSDsoft Express configuration.
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Doc ID 7833 Rev 7
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