UPSD3422_06 Datasheet, PDF (252/293 Pages) STMicroelectronics – Turbo Plus Series Fast Turbo 8032 MCU with USB and Programmable Logic

PSD module
uPSD34xx
28.6.2
firmware needs to be present for ISP. This is good for manufacturing, for field updates, and
for easy code development in the lab. JTAG-based programmers and debuggers for
uPSD34xx are available from STMicroelectronics and 3rd party vendors.
ISP is different than IAP (In-Application Programming). IAP involves the 8032 to program
Flash memory over any interface supported by the 8032 (e.g., UART, SPI, I2C), which is
good for remote updates over a communication channel. uPSD34xx devices support both
ISP and IAP. The entire PSD Module (Flash memory and PLD) may be programmed with
JTAG ISP, but only the Flash memories may be programmed using IAP.
JTAG chaining inside the package
JTAG protocol allows serial “chaining” of more than one device in a JTAG chain. The
uPSD34xx is assembled with a stacked die process combining the PSD Module (one die)
and the MCU Module (the other die). These two die are chained together within the
uPSD34xx package. The standard JTAG interface has four basic signals:
● TDI - Serial data into device
● TDO - Serial data out of device
● TCK - Common clock
● TMS - Mode Selection
Every device that supports IEEE 1149.1 JTAG communication contains a Test Access Port
(TAP) controller, which is a small state machine to manage JTAG protocol and serial
streams of commands and data. Both the PSD Module and the MCU Module each contain a
TAP controller.
Figure 91 illustrates how these die are chained within a package. JTAG programming/test
equipment will connect externally to the four IEEE 1149.1 JTAG pins on Port C. The TDI pin
on the uPSD34xx package goes directly to the PSD Module first, then exits the PSD Module
through TDO. TDO of the PSD Module is connected to TDI of the MCU Module. The serial
path is completed when TDO of the MCU Module exits the uPSD34xx package through the
TDO pin on Port C. The JTAG signals TCK and TMS are common to both modules as
specified in IEEE 1149.1. When JTAG devices are chained, typically one devices is in
BYPASS mode while another device is executing a JTAG operation. For the uPSD34xx, the
PSD Module is in BYPASS mode while debugging the MCU Module, and the MCU Module
is in BYPASS mode while performing ISP on the PSD Module.
The RESET_IN input pin on the uPSD34xx package goes to the MCU Module, and this
module will generate the RST reset signal for the PSD Module. These reset signals are
totally independent of the JTAG TAP controllers, meaning that the JTAG channel is
operational when the modules are held in reset. It is required to assert RESET_IN during
ISP. STMicroelectronics and 3rd party JTAG ISP tools will automatically assert a reset signal
during ISP. However, the user must connect this reset signal to RESET_IN as shown in
examples in Figure 92 on page 254 and Figure 93 on page 255.
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