PSD4235G2V-10U STMICROELECTRONICS [STMicroelectronics], PSD4235G2V-10U Datasheet - Page 75

• Manufacturer Part Number: PSD4235G2V-10U
• Description: Flash In-System Programmable (ISP) Peripherals for 16-bit MCUs
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Figure 34. Reset (RESET) Timing
PROGRAMMING IN-CIRCUIT USING THE JTAG SERIAL INTERFACE
The JTAG Serial Interface on the PSD can be en-
abled on Port E (see Table 52). All memory blocks
(primary Flash memory and secondary Flash
memory), PLD logic, and PSD Configuration bits
may be programmed through the JTAG-ISC Serial
Interface. A blank device can be mounted on a
printed circuit board and programmed using JTAG
In-System Programming (ISP).
The standard JTAG signals (IEEE 1149.1) are
TMS, TCK, TDI, and TDO. Two additional signals,
TSTAT and TERR, are optional JTAG extensions
used to speed up Program and Erase cycles.
By default, on a blank PSD (as shipped from the
factory, or after erasure), four pins on Port E are
enabled for the basic JTAG signals TMS, TCK,
TDI, and TDO .
See Application Note AN1153 for more details on
JTAG In-System Programming (ISP).
Standard JTAG Signals
The standard JTAG signals (TMS, TCK, TDI, and
TDO) can be enabled by any of three different con-
ditions that are logically ORed. When enabled,
TDI, TDO, TCK, and TMS are inputs, waiting for a
serial command from an external JTAG controller
device (such as FlashLINK or Automated Test
Equipment). When the enabling command is re-
ceived from the external JTAG controller device,
TDO becomes an output and the JTAG channel is
fully functional inside the PSD. The same com-
mand that enables the JTAG channel may option-
ally enable the two additional JTAG pins, TSTAT
and TERR.
The following symbolic logic equation specifies the
conditions enabling the four basic JTAG pins
(TMS, TCK, TDI, and TDO) on their respective
Port E pins. For purposes of discussion, the logic
label JTAG_ON is used. When JTAG_ON is true,
the four pins are enabled for JTAG. When
JTAG_ON is false, the four pins can be used for
general PSD I/O.
This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice.
V
RESET
CC
Power-On Reset
V
t NLNH-PO
CC
(min)
t OPR
JTAG_ON = PSDsoft_enabled +
Microcontroller_enabled +
PSD_product_term_enabled;
/* An NVM configuration bit inside
the PSD is set by the designer in
the PSDsoft Configuration utili-
ty. This dedicates the pins for
JTAG at all times (compliant with
IEEE 1149.1 */
/* The microcontroller can set a
bit at run-time by writing to the
PSD register, JTAG Enable. This
register
CSIOP + offset C7h. Setting the
JTAG_ENABLE bit in this register
will enable the pins for JTAG use.
This bit is cleared by a PSD reset
or the microcontroller. See Table
21 for bit definition. */
/* A dedicated product term (PT)
inside the PSD can be used to en-
able the JTAG pins. This PT has
the reserved name JTAGSEL. Once
defined as a node in PSDabel, the
designer can write an equation for
JTAGSEL. This method is used when
the Port E JTAG pins are multi-
plexed with other I/O signals. It
is recommended to tie logically
the node JTAGSEL to the JEN\ sig-
nal on the Flashlink cable when
multiplexing JTAG signals. See Ap-
plication Note 1153 for details.
*/
is
Warm Reset
t NLNH-A
t NLNH
located
PSD4256G6V
t OPR
at
AI02866b
address
75/100