PSD935G2-90U STMicroelectronics, PSD935G2-90U Datasheet - Page 33

• Manufacturer Part Number: PSD935G2-90U
• Manufacturer: STMicroelectronics

Specifications of PSD935G2-90U

• Operating Temperature (max): 70C
• Operating Temperature (min): 0C
• Operating Temperature Classification: Commercial
• Package Type: TQFP
• Mounting: Surface Mount
• Pin Count: 80
• Lead Free Status / RoHS Status: Compliant

The
PSD935G2
Functional
Blocks
(cont.)
32
PSD9XX Family
NOTE: The address inputs are A[19:4] in 80C51XA mode.
9.2 PLDs
The PLDs bring programmable logic functionality to the PSD935G2. After specifying the
logic for the PLDs in PSDsoft, the logic is programmed into the device and available upon
power-up.
The PSD935G2 contains two PLDs: the Decode PLD (DPLD), and the General Purpose
PLD (GPLD). The PLDs are briefly discussed in the next few paragraphs, and in more
detail in sections 9.2.1 and 9.2.2. Figure 11 shows the configuration of the PLDs.
The DPLD performs address decoding for internal components, such as memory,
registers, and I/O port selects.
The GPLD can be used to generate external chip selects, control signals or logic functions.
The GPLD has 24 outputs that are connected to Port A, B and C.
The AND array is used to form product terms. These product terms are specified using
PSDsoft. An Input Bus consisting of 66 signals is connected to the PLDs. The signals are
shown in Table 12. The complement of the 66 signals are also available as inputs to the
AND array.
Table 12. DPLD and GPLD Inputs
The Turbo Bit
The PLDs in the PSD935G2 can minimize power consumption by switching to standby
when inputs remain unchanged for an extended time of about 70 ns. Setting the Turbo
mode bit to off (Bit 3 of the PMMR0 register) automatically places the PLDs into standby if
no inputs are changing. Turbo-off mode increases propagation delays while reducing
power consumption. Refer to the Power Management Unit section on how to set the Turbo
Bit. Additionally, five bits are available in the PMMR2 register to block MCU control signals
from entering the PLDs. This reduces power consumption and can be used only when
these MCU control signals are not used in PLD logic equations.
MCU Address Bus
MCU Control Signals
Reset
Power Down
Port A Input
Port B Input
Port C Input
Port D Inputs
Port F Inputs
Page Register
Flash Programming Status Bit
Input Source
A[15:0]
CNTL[2:0]
RST
PDN
PA[7-0]
PB[7-0]
PC[7-0]
PD[3:0]
PF[7:0]
PGR(7:0)
Rdy/Bsy
Input Name
*
PSD935G2
of Signals
Number
16
3
1
1
8
8
8
4
8
8
1