PSD813F2V Datasheet, PDF (70/110 Pages) STMicroelectronics – Flash In-System Programmable (ISP) Peripherals for8-bits MCUs, 3V

PSD813F2V, PSD833F2V, PSD853F2V, PSD854F2V
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 speed Program
and Erase cycles by indicating status on PSD sig-
nals instead of having to scan the status out seri-
ally using the standard JTAG channel. See
Application Note AN1153.
TERR indicates if an error has occurred when
erasing a sector or programming a byte in Flash
memory. This signal goes Low (active) when an
Error condition occurs, and stays Low until an
“ISC_CLEAR” command is executed or a chip Re-
set (RESET) pulse is received after an
“ISC_DISABLE” command.
TSTAT behaves the same as Ready/Busy de-
scribed in the section entitled Ready/Busy
(PC3), page 20. TSTAT is High when the PSD de-
vice is in READ Mode (primary and secondary
Flash memory contents can be read). TSTAT is
Low when Flash memory Program or Erase cycles
are in progress, and also when data is being writ-
ten to the secondary Flash memory.
TSTAT and TERR can be configured as open-
drain type signals during an “ISC_ENABLE” com-
mand. This facilitates a wired-OR connection of
TSTAT signals from multiple PSD devices and a
wired-OR connection of TERR signals from those
same devices. This is useful when several PSD
devices are “chained” together in a JTAG environ-
ment.
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 era-
sures. The sector protect bits can be set in PSD-
soft Express Configuration.
Table 34. JTAG Port Signals
Port C Pin JTAG Signals
Description
PC0
TMS
Mode Select
PC1
TCK
Clock
PC3
TSTAT
Status
PC4
TERR
Error Flag
PC5
TDI
Serial Data In
PC6
TDO
Serial Data Out
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