UPSD3254 STMICROELECTRONICS [STMicroelectronics], UPSD3254 Datasheet - Page 137

• Manufacturer Part Number: UPSD3254
• Description: Flash Programmable System Devices with 8032 Microcontroller Core
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

PLD Power Management
The power and speed of the PLDs are controlled
by the Turbo Bit (Bit 3) in PMMR0. By setting the
bit to '1,' the Turbo Mode is off and the PLDs con-
sume the specified stand-by current when the in-
puts are not switching for an extended time of
70ns. The propagation delay time is increased by
10ns (for a 5V device) after the Turbo Bit is set to
'1' (turned off) when the inputs change at a com-
posite frequency of less than 15MHz. When the
Turbo Bit is reset to '0' (turned on), the PLDs run
at full power and speed. The Turbo Bit affects the
PLD’s DC power, AC power, and propagation de-
lay. When the Turbo Mode is off, the uPSD325X
devices’ input clock frequency is reduced by 5MHz
from the maximum rated clock frequency.
Blocking MCU control signals with the bits of
PMMR2 can further reduce PLD AC power con-
sumption.
SRAM Standby Mode (Battery Backup). The
SRAM in the PSD MODULE supports a battery
backup mode in which the contents are retained in
the event of a power loss. The SRAM has Voltage
Stand-by (V
an external battery. When V
than V
nects to Voltage Stand-by (V
er source. The SRAM Standby Current (I
typically 0.5 µA. The SRAM data retention voltage
is
(V
cates when the V
Table 101. Power Management Mode Registers PMMR0
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
BATON
2V
STBY
) can be routed to PC4. This signal indi-
X
APD Enable
X
PLD Turbo
PLD Array clk
PLD MCell clk
X
X
minimum.
STBY
then the SRAM automatically con-
, PC2) that can be connected to
CC
has dropped below V
The
0
0 = off Automatic Power-down (APD) is disabled.
1 = on Automatic Power-down (APD) is enabled.
0
0 = on PLD Turbo Mode is on
1 = off
0 = on
1 = off CLKIN (PD1) input to PLD AND Array is disconnected, saving power.
0 = on CLKIN (PD1) input to the PLD macrocells is connected.
1 = off CLKIN (PD1) input to PLD macrocells is disconnected, saving power.
0
0
Battery-on
STBY
CC
Not used, and should be set to zero.
Not used, and should be set to zero.
PLD Turbo Mode is off, saving power.
uPSD325X devices operate at 5MHz below the maximum rated clock frequency
CLKIN (PD1) input to the PLD AND Array is connected. Every change of CLKIN
(PD1) Powers-up the PLD when Turbo Bit is '0.'
Not used, and should be set to zero.
Not used, and should be set to zero.
, PC2) as a pow-
becomes lower
UPSD3254A, UPSD3254BV, UPSD3253B, UPSD3253BV
Indicator
STBY
STBY
) is
.
PSD Chip Select Input (CSI, PD2)
PD2 of Port D can be configured in PSDsoft Ex-
press as PSD Chip Select Input (CSI). When Low,
the signal selects and enables the PSD MODULE
Flash memory, SRAM, and I/O blocks for READ or
WRITE operations. A High on PSD Chip Select In-
put (CSI, PD2) disables the Flash memory, and
SRAM, and reduces power consumption. Howev-
er, the PLD and I/O signals remain operational
when PSD Chip Select Input (CSI, PD2) is High.
Input Clock
CLKIN (PD1) can be turned off, to the PLD to save
AC power consumption. CLKIN (PD1) is an input
to the PLD AND Array and the Output Macrocells
(OMC).
During Power-down Mode, or, if CLKIN (PD1) is
not being used as part of the PLD logic equation,
the clock should be disabled to save AC power.
CLKIN (PD1) is disconnected from the PLD AND
Array or the Macrocells block by setting Bits 4 or 5
to a '1' in PMMR0.
Input Control Signals
The PSD MODULE provides the option to turn off
the MCU signals (WR, RD, PSEN, and Address
Strobe (ALE)) to the PLD to save AC power con-
sumption. These control signals are inputs to the
PLD AND Array. During Power-down Mode, or, if
any of them are not being used as part of the PLD
logic equation, these control signals should be dis-
abled to save AC power. They are disconnected
from the PLD AND Array by setting Bits 2, 3, 4, 5,
and 6 to a '1' in PMMR2.
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