C8051F046-GQ Silicon Laboratories Inc, C8051F046-GQ Datasheet - Page 163

• Manufacturer Part Number: C8051F046-GQ
• Description: IC 8051 MCU 32K FLASH 100TQFP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F04xr

Specifications of C8051F046-GQ

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: CAN, EBI/EMI, SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 64
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: FLASH
• Ram Size: 4.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 13x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 100-TQFP, 100-VQFP
• Processor Series: C8051F0x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 4.25 KB
• Interface Type: CAN, SMBus, SPI, UART
• Maximum Clock Frequency: 25 MHz
• Number Of Programmable I/os: 64
• Number Of Timers: 5
• Operating Supply Voltage: 2.7 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Development Tools By Supplier: C8051F040DK
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 13 Channel
• On-chip Dac: 12 bit, 2 Channel
• Package: 100TQFP
• Device Core: 8051
• Family Name: C8051F04x
• Maximum Speed: 25 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details
• Other names: 336-1211

12.17. Power Management Modes
The CIP-51 core has two software programmable power management modes: Idle and Stop. Idle mode
halts the CPU while leaving the external peripherals and internal clocks active. In Stop mode, the CPU is
halted, all interrupts and timers (except the Missing Clock Detector) are inactive, and the internal oscillator
is stopped. Since clocks are running in Idle mode, power consumption is dependent upon the system clock
frequency and the number of peripherals left in active mode before entering Idle. Stop mode consumes the
least power. SFR Definition 12.18 describes the Power Control Register (PCON) used to control the CIP-
51's power management modes.
Although the CIP-51 has Idle and Stop modes built in (as with any standard 8051 architecture), power
management of the entire MCU is better accomplished by enabling/disabling individual peripherals as
needed. Each analog peripheral can be disabled when not in use and put into low power mode. Digital
peripherals, such as timers or serial buses, draw little power whenever they are not in use. Turning off the
oscillator saves even more power, but requires a reset to restart the MCU.
12.17.1.Idle Mode
Setting the Idle Mode Select bit (PCON.0) causes the CIP-51 to halt the CPU and enter Idle mode as soon
as the instruction that sets the bit completes.
data. All analog and digital peripherals can remain active during Idle mode.
Idle mode is terminated when an enabled interrupt or /RST is asserted. The assertion of an enabled inter-
rupt will cause the Idle Mode Selection bit (PCON.0) to be cleared and the CPU to resume operation. The
pending interrupt will be serviced and the next instruction to be executed after the return from interrupt
(RETI) will be the instruction immediately following the one that set the Idle Mode Select bit. If Idle mode is
terminated by an internal or external reset, the CIP-51 performs a normal reset sequence and begins pro-
gram execution at address 0x0000.
If enabled, the WDT will eventually cause an internal watchdog reset and thereby terminate the Idle mode.
This feature protects the system from an unintended permanent shutdown in the event of an inadvertent
write to the PCON register. If this behavior is not desired, the WDT may be disabled by software prior to
entering the Idle mode if the WDT was initially configured to allow this operation. This provides the oppor-
tunity for additional power savings, allowing the system to remain in the Idle mode indefinitely, waiting for
an external stimulus to wake up the system. Refer to
configuration of the WDT.
Note: Any instruction that sets the IDLE bit should be immediately followed by an instruction that has 2 or
more opcode bytes. For example:
// in 'C':
PCON |= 0x01;
PCON

; in assembly:
ORL PCON, #01h
MOV PCON, PCON
If the instruction following the write of the IDLE bit is a single-byte instruction and an interrupt occurs during
the execution phase of the instruction that sets the IDLE bit, the CPU may not wake from IDLE mode when
a future interrupt occurs.
= PCON;
// set IDLE bit
// ... followed by a 3-cycle dummy instruction
; set IDLE bit
; ... followed by a 3-cycle dummy instruction
All internal registers and memory maintain their original
Rev. 1.5
Section 13.7
C8051F040/1/2/3/4/5/6/7
for more information on the use and
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