4.5 ISP via JTAG Port
In-System Programming can be performed through the JTAG pins on Port E. This serial
interface allows complete programming of the entire PSD835G2 device. A blank device
can be completely programmed. The JTAG signals (TMS, TCK, TSTAT, TERR, TDI, TDO)
can be multiplexed with other functions on Port E. Table 3 indicates the JTAG signals pin
4.6 In-System Programming (ISP)
Using the JTAG signals on Port E, the entire PSD835G2 (memory, logic, configuration)
device can be programmed or erased without the use of the microcontroller.
Table 3. JTAG Signals on Port E
Port E Pins
4.7 In-Application re-Programming (IAP)
The main Flash memory can also be programmed in-system by the microcontroller
executing the programming algorithms out of the secondary Flash memory, or SRAM.
Since this is a sizable separate block, the application can also continue to operate. The
secondary Flash boot memory can be programmed the same way by executing out of the
main Flash memory. Table 4 indicates which programming methods can program different
functional blocks of the PSD8XX.
Table 4. Methods of Programming Different Functional Blocks of the PSD835G2
Main Flash memory
Flash Boot memory
PLD Array (DPLD and CPLD)
4.8 Page Register
The eight-bit Page Register expands the address range of the microcontroller by up to
256 times.The paged address can be used as part of the address space to access
external memory and peripherals or internal memory and I/O. The Page Register can also
be used to change the address mapping of blocks of Flash memory into different memory
spaces for IAP.
4.9 Power Management Unit
The Power Management Unit (PMU) in the PSD835G2 gives the user control of the
power consumption on selected functional blocks based on system requirements. The
PMU includes an Automatic Power Down unit (APD) that will turn off device functions due
to microcontroller inactivity. The APD unit has a Power Down Mode that helps reduce
The PSD835G2 also has some bits that are configured at run-time by the MCU to reduce
power consumption of the CPLD. The turbo bit in the PMMR0 register can be turned off
and the CPLD will latch its outputs and go to standby until the next transition on its inputs.
Additionally, bits in the PMMR2 register can be set by the MCU to block signals from
entering the CPLD to reduce power consumption. See section 9.5.