C8051F046-GQ Silicon Laboratories Inc, C8051F046-GQ Datasheet - Page 153

• 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

12.3. Interrupt Handler
The CIP-51 includes an extended interrupt system supporting a total of 20 interrupt sources with two prior-
ity levels. The allocation of interrupt sources between on-chip peripherals and external inputs pins varies
according to the specific version of the device. Each interrupt source has one or more associated interrupt-
pending flag(s) located in an SFR. When a peripheral or external source meets a valid interrupt condition,
the associated interrupt-pending flag is set to logic 1.
If interrupts are enabled for the source, an interrupt request is generated when the interrupt-pending flag is
set. As soon as execution of the current instruction is complete, the CPU generates an LCALL to a prede-
termined address to begin execution of an interrupt service routine (ISR). Each ISR must end with an RETI
instruction, which returns program execution to the next instruction that would have been executed if the
interrupt request had not occurred. If interrupts are not enabled, the interrupt-pending flag is ignored by the
hardware and program execution continues as normal. The interrupt-pending flag is set to logic 1 regard-
less of the interrupt's enable/disable state.
Each interrupt source can be individually enabled or disabled through the use of an associated interrupt
enable bit in an SFR (IE-EIE2). However, interrupts must first be globally enabled by setting the EA bit
(IE.7) to logic 1 before the individual interrupt enables are recognized. Setting the EA bit to logic 0 disables
all interrupt sources regardless of the individual interrupt-enable settings.
Note: Any instruction that clears the EA bit should be immediately followed by an instruction that has two
or more opcode bytes. For example:

// in 'C':
EA = 0;
EA = 0;

; in assembly:
CLR
CLR
If an interrupt is posted during the execution phase of a "CLR EA" opcode (or any instruction which clears
the EA bit), and the instruction is followed by a single-cycle instruction, the interrupt may be taken. How-
ever, a read of the EA bit will return a '0' inside the interrupt service routine. When the "CLR EA" opcode is
followed by a multi-cycle instruction, the interrupt will not be taken.
Some interrupt-pending flags are automatically cleared by the hardware when the CPU vectors to the ISR.
However, most are not cleared by the hardware and must be cleared by software before returning from the
ISR. If an interrupt-pending flag remains set after the CPU completes the return-from-interrupt (RETI)
instruction, a new interrupt request will be generated immediately and the CPU will re-enter the ISR after
the completion of the next instruction.
12.3.1. MCU Interrupt Sources and Vectors
The MCUs support 20 interrupt sources. Software can simulate an interrupt event by setting any interrupt-
pending flag to logic 1. If interrupts are enabled for the flag, an interrupt request will be generated and the
CPU will vector to the ISR address associated with the interrupt-pending flag. MCU interrupt sources,
associated vector addresses, priority order and control bits are summarized in Table 12.4. Refer to the
datasheet section associated with a particular on-chip peripheral for information regarding valid interrupt
conditions for the peripheral and the behavior of its interrupt-pending flag(s).
EA
EA
// clear EA bit
// ... followed by another 2-byte opcode
; clear EA bit
; ... followed by another 2-byte opcode
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